Two characters are, as far as the audience are concerned, not romantically involved with each other. Maybe they're Just Friends, co-workers, or perhaps even strangers. Then those characters get Put on a Bus, or become Out of Focus, or the story gets a Time Skip. And when the audience see those the pair again, they're already a couple, maybe even married.
Basically, this is an inversion of an Offscreen Breakup, where the writers can justify pairing the two people together without having to dedicate a Romance Arc around them. It is commonly invoked to prevent a Romantic Plot Tumour (if the story is not centered around romance), or to avert Offscreen Inertia, but this could also lead to accusations of Strangled by the Red String if not handled carefully.
Compare Married in the Future, where characters who are already in a relationship consolidate their ties after a Time Skip or in an Alternate Universe, and Last-Minute Hookup, where characters are abruptly paired off in the finale, but the upgrade doesn't necessarily have to happen off-screen.
Note: This trope only counts when the couple has a Relationship Upgrade in mid-story. It doesn't qualify if they are introduced as a couple from the get-go.
- Most pairings in Dragon Ball and its continuities (though Gohan/Videl actually averts it, since the two take a while to develop their feelings). A few characters marry and have kids during the series's frequent time skips with little on-screen development. To the author's credit, the reason for the lack of development is because he's stated in interviews that he doesn't care for romance, and most of the couples hook up during a Time Skip of several years, allowing the readers' imaginations to run wild.
- Played for Laughs in Kaguya-sama: Love is War, when Osaragi casually reveals during the culture festival that she's been dating the captain of the cheer team for the past several weeks (whom she had previously interacted with onscreen a grand total of once). This comes as a complete shock to her best friend Miko. And then they break up a week or so later (also off-screen). It's later implied that the only reason she was dating him was because she viewed him as a threat to Ishigami getting together Tsubame, which explains why she ended the relationship so soon after Ishigami's confession.
- In Lyrical Nanoha, Chrono and Amy go from snarky colleagues to married-with-two-children during the Time Skip between A's and StrikerS seasons, though some off-handed comments imply this was more of a Shotgun Wedding. Likewise, Griffith and Lucino complete their romance arc off-screen between StrikerS and Force and are married in the latter.
- Downplayed by Asuma and Kurenai since they at least have one moment where they're walking together and Kakashi accused them of dating (which they try to deny). After the Time Skip, we only see they're married after we see Kurenai with a wedding ring... and not long after that, Asuma died in battle by Hidan's hands.
- Played straight by the parents of Inojin whose parents had one misleading interaction during the series, Chocho whose parents never interacted at all and Metal Lee who's parents consist of Rock Lee and an unknown person.
- The finale of Negima! Magister Negi Magi implies that Satomi Hakase would eventually marry Kurt Gödel, whom she has never even met over the course of the series.
- One Piece: Oda has stated that he isn't very good at writing romance, so this is to be expected; one example is how Mr. 9 and Miss Monday hooking up with a child after the Time Skip when, in their previous appearances, they only interact as fellow members of Baroque Works. Subverted, however, by Rebecca's parents Kyros and Scarlet; there's a dedicated flashback story about how the two get together, even if it's mostly shown in short romantic montages.
- In Random Walk, Touko's relationship with her on-and-off boyfriend Tsukasa oscillates between this trope and Offscreen Breakup. The couple first meet when Tsukasa foils Touko's plan to trick the guys into paying for their entertainment, and Touko complains about the incident when she encounters him again at school. The next time she talks about him, she reveals they're together. Then they break up because of an off-screen argument. This happens several time, and the audience only gets to see the end-result after Touko announces the fact to her friends and their reactions toward it.
- Sengoku Youko: Over the 8-year Time Skip, Raidou marries an ex-palace attendant and start a family with her.
- UQ Holder! has Negi marry Chisame in the A Prime timeline, even though she is shown to reject his Love Confession in an earlier scene. This is lampshaded by Dana, who says that the manga doesn't have enough pages to show Chisame change her mind.
- In Diamond and Silver's Excellent Adventure, Twilight Sparkle's very first scene with Baron Zeppeli—at the end of the fic—establishes that they've been a couple for some months, offscreen. (Time travel was involved.) Mainly this came about because the entire fic was a Round Robin, and the author who wrote this part thought a sudden relationship between them would be funny.
- In East, Harald Soren learns about Sara's existence early in part two. Then many chapters go by without them talking to each other (or even about each other), and in the end of part three, they are in love and engaged. Justified both out of universe (their relationship is completely unrelated to the main plot) and In-Universe (they only reveal it to the POV characters after the engagement).
- In Further Tales of the City, Mary Ann and Brian, previously portrayed as just housemates, are shown to have become engaged since the end of the previous book.
- Tonks and Lupin are revealed to be in love at the end of Harry Potter and the Half-Blood Prince. Neither Harry nor the audience saw the relationship develop, so this comes as quite a surprise — especially since, in the beginning of the book, Harry actually thought that Tonks was in love with Sirius instead (because she started behaving strangely after his death). The two got married some time between the sixth and seventh book, but the event is only given a brief mention in the prologue of Harry Potter and the Deathly Hallows. This is largely understandable since with very few exceptions the story is told solely from Harry's perspective, so the audience only sees what Harry sees. Tonks and Lupin's romance was off-page because it happened while Harry was at school and neither of them had a job at Hogwarts, so naturally he didn't see any of it until they were already an established couple.
- In Ramona Forever, Aunt Bea mentions that she and Mrs. Quimby used to go to the same school as Howie's visiting uncle, Hobart, but otherwise made no indication that the two personally know each other — and, as far as Ramona is concerned, her aunt is seeing a man named Michael. Partway through the book, there are talks about Howie's uncle dating a teacher, whom Ramona suspects is her Aunt. This is later confirmed on-screen when Uncle Hobart and Aunt Bea shows up at dinner and announce that they're getting married. Even though the readers are given plenty of foreshadow regarding the couple's relationship before its reveal, they still did not see how exactly their romance unfold. At least the wedding takes place on-screen though, and the occasion serves as the book's climax.
- It's implied that at some point between when Skitter turns herself in to the Protectorate and later becomes the superhero Weaver, and the final battles with Scion that her henchmen Forrest and Charlotte became a couple.
- The supervillian mercenaries Gregor the Snail and Shamrock are seen as part of Faultine's crew in the beginning, but there's no hint of romance between them. By the time of Faultline's Interlude around the midpoint of the story, however, they're seen holding hands and are implied to have become a couple offscreen.
- Corner Gas has Brent and Lacey in a relationship for two years by the time of Corner Gas The Movie
- Doctor Who had Martha and Mickey unexpectedly start a relationship somewhere between "The Stolen Earth"/"Journeys' End" and "The End of Time", even though Martha had previously been depicted as being engaged to a different man.
- In the early seasons of Monk, there was a bit of Ship Tease between Sharona and Randy (she happened across a personal ad he had placed matching her description), but for the most part, they were simply portrayed as somewhat argumentative friends. In the last episode, it's revealed that Randy is moving departments to be close to Sharona, with whom he's apparently become involved offscreen.
- Aveyond 3: If the player doesn't marry Mel to Edward at the end of The Darkthrop Prophecy, the "Where Are They Now?" Epilogue would mention that she'd eventually marry a man named Lars VIII, who never actually show up in the games proper. Word of God says that this is actually the canon Official Couple she had in mind.
- The epilogue of Eternal Eden shows that Fierro and Josefine are engaged to one another, despite not having any romantic interactions throughout their journey together, owing to the fact that the latter was only introduced somewhere around the story's climax, and the former had spent a large portion of his screen-time pining after Jean (whom he insists is a woman). The game's justification is that the epilogue takes place after a Cosmic Retcon, and the two probably had a more developed romance in the new continuity that the protagonist knew nothing about.
- In Fire Emblem Awakening characters form friendly/romantic bonds by fighting side by side. The protagonist Chrom is in a special case because the plot will force him to be married by end of the eleventh main story-related battle no matter what. If the player didn't already marry him off at that point, the game will automatically give him a wife. Olivia becomes an available combatant during the very battle at the end of which he has to be married, in contrast to the 3-4 note other candidates with whom a proper romance is possible. That battle is Chrom's only chance to befriend Olivia before his wedding and they need to fight side by side a minimum number of times to get married, making them a very narrowly averted case of this trope note . There is however a straight case in the game: if Chrom can marry neither Olivia nor any of the "proper romance" candidates, the mother of his baby daughter after the two-year Time Skip will be a Satellite Love Interest simply known as "Maiden" depicted with a generic female villager portrait and with literally no other role in the story. Dialogue will imply that Chrom met, romanced and married her, all during the Time Skip.
- Makena and Sabo of The Journey Down are first seen in Chapter One and never interact with each other. Later in Chapter Three, we find out they eventually met (Makena had been evicted from her joint in Kingsport Bay); being both cooks, they were a perfect match, and they now run a restaurant in St. Armando together.
- Due to the open world nature of The Sims 3, Sims who are not in the player's active household can start to romance and even get married to other Sims, even if they are not romantically involved with anyone the last time the player controlled them.
- A few of these slip by in Homestuck's many timeskips.
- The audience first learns that Jade and Davesprite were dating when she announces their breakup.
- Another example is Gamzee and Terezi's abusive black romance, which the audience very rarely gets to see play out on screen, with most of its coverage until the very end of the relationship and timeline consisting of the negative effects that it's having on Terezi and the other characters reacting to it.
- Similarly, it was implied and later confirmed that Dave and Terezi were dating for much of the first two years of the timeskips, but only through conversations with them or other characters; their actual relationship was not shown at all, and they were only rarely shown interacting during that time, before Dave revealed in the third year that they, like Davesprite and Jade, had an Offscreen Breakup.
- Another couple, Dave and Karkat, had this work against them, as the audience can see they got much closer during the Retcon timeline but how and why is left so vague that the relationship's nature and quadrant (and whether they were Strangled by the Red String) is a major point of fandom debate.
- Dark Star and Phala of L's Empire had no hint of attraction to one another when they met. Cue two weeks later, and they had a son off-screen (the mechanics behind the conception and fast pregnancy were Handwaved with "we were drunk at the time").
- Stand Still, Stay Silent has a Just Before the End sequence that focuses on various people that would go on to be the ancestors of the main characters introduced 90 years later. A couple of the sequences cause this:
- The main characters of the Norway sequence are a group of four friends made of two men and two women. Neither of them seem romantically involved with each other. The descendant of one of the pairs has her great-grandmother's first name, which is the only in-story hint of how these friends ended up pairing up aside from two easy to miss portraits seen in a flash-back.
- The Denmark sequence has the members of a future couple meeting for the first time. The man has family in the area in which they end up stuck because of the disaster. Before we see their descendant, the only hint of the two of them going somewhere romantically is a Time Skip photo that shows that the woman is staying with the man's family.
- In Yet Another Fantasy Gamer Comic, Sir Aeden got married to a certain Lady Vivay after being rendered Out of Focus for a while.
- Beckett, Reversal's best friend in Roll to Breathe is suddenly seen with a date to the Spring Fling. Said date is Prism, known metahuman delinquent and a member of a rival group to the Final Hazard. The two are then referred to as boyfriend and girlfriend, with no explanation as to how or why they are dating.