* ActorAllusion: Jo Wilson, played by Camilla Luddington, whose StarMakingRole was as [[BritishRoyalFamily Kate Middleton]], is referred to as "Princess" by Alex.
* DirectedByCastMember: Kevin [=McKidd=] and Chandra Wilson have both spent time behind the camera.
* ExecutiveMeddling:
** There were originally four core interns, but producers felt that another male intern should be added. Enter Alex, who had to be both digitally added to the pilot and required new scenes to be filmed. Considering Alex is one of the most beloved characters on the show, it is an example of this trope turning out well.
** Budget cuts for Season 9 were partly to blame for [[spoiler: the loss of three regular characters]].
* FakeAmerican: Jo Wilson is played by an English actress, while Kevin [=McKidd=] is Scottish.
** And Cristina is played by Canadian Sandra Oh.
* [[HeyItsThatGuy Hey, It's That Girl!]]: Before she went to med school, Erica was [[TheSilenceOfTheLambs kidnapped by a serial killer who wanted to]] ''[[TheSilenceOfTheLambs turn her into a woman suit]]??''
** Lexie Grey [[SheCleansUpNicely cleaned up nicely]]. I mean... she used to ... [[NotAnotherTeenMovie have a ponytail... and... glasses... and... those paint-covered overalls!!!]]
** And before she was an InsufferableGenius doctor, Cristina was an InsufferableGenius personal assistant to a SmallNameBigEgo [[Series/{{Arliss}} sports agent]]...
*** And [[WakingTheDead a Korean Immigrant in the '80s]], and [[{{Sideways}} a wine expert]]...
*** And admirably surviving [[LastNight the end of the world in Toronto]].
**** Actually she dies.
*** She also dated Addison, seriously. Watch Under the Tuscan Sun.
*** She was also [[Film/ThePrincessDiaries the principal of Mia Thermopolis's high school]].
** Calli was a hooker in a blue dress and blonde wig that was questioned by Benson and Stabler.
** Meredith dated [[{{NCISLosAngeles}} G. Callen]]...who was a vet before becoming a Navy cop.
** Izzie is actually [[{{Roswell}} an alien]]...
*** Who was also named Izzie and in love with '''another''' guy named Alex, no less!
** [[TheWoobie Alex]] used to be [[Series/ColdCase a diabetic detective in Philly]].
** And, as it turns out [[FreaksAndGeeks Jesus is just alright with]] Devo, the Orthodox Jew who gets a cow valve for her failing heart in season 1. Her name is Madeline Zima.
*** That's actually Sarah Hagan. So Devo was a [[Series/BuffyTheVampireSlayer Potential Slayer]] in a past life.
** Before joining the US army (and I mean a little over 2000 years before) Owen Hunt was [[Series/{{Rome}} a centurion of Caesar's 13th legion]].
*** Not to mention if Seattle Grace is ever under [[Film/DogSoldiers werewolf]] attack, Hunt will save the day!
*** And apparently one of his former army buddies is [[Series/TwentyFour Audrey Raines]].
*** Also, he's [[ModernWarfare Capt. 'Soap' McTavish]].
*** And he's the descendant of a tenor that sang for [[Film/TopsyTurvy Gilbert and Sullivan]]
*** He also died of [[Literature/{{Trainspotting}} AIDS that time]]
** Lord John Marbury and Zoey Bartlet also show up in consecutive episodes.
** Both of Amy Abbott's best friends from {{Everwood}} show up as residents when the merger takes place.
** Meredith used to make out with [[Series/{{Friends}} Chandler]]. Like, a lot.
** Who knew that Arizona already had a kid, with Series/{{Bo|nes}}oth?
*** And Denny Duquette [[Series/{{Supernatural}} hunts demons]] in his spare time.
**** And [[Film/{{Watchmen}} fights crime]].
** Not to mention that Gary Clark was previously in charge of protecting [[Series/TheWestWing President Bartlett]], not shooting people.
*** In addition the Chief was the Mayor of DC on ''The West Wing''.
** April Kepner has come a long way since her days in [[WesternAnimation/{{Daria}} the Fashion Club]]...
*** She also played a killer on ''Series/{{Castle}}''.
*** And let's not forget her turn as Hannah on {{Everwood}}
** Hey, It's [[GilmoreGirls Richard Gilmore, Mrs. Kim and Paris Geller!]]
** Dylan Young is the IdenticalGrandson of 1930's film star, [[Film/KingKong Bruce Baxter]].
** And now Owen is possibly cheating on Cristina with... [[SummerGlau River Tam]]?? (Well, okay, we can't blame him for that, but still.)
** [[Series/FridayNightLights Smash]] went to medical school.
** [[Series/BoyMeetsWorld Mr. Feeny]] (aka Creator/WilliamDaniels) moved to Minnesota and became a cardiothoratic surgeon. Or was it [[Series/StElsewhere gifted heart surgeon Dr. Mark Craig]]?
** [[QueerAsFolk Brian Kinney]] is a white supremacist.
** [[Series/VeronicaMars Mac]] is now a medical intern.
** [[Series/OneTreeHill Peyton Sawyer]] (Hilarie Burton) moved to Seattle and became a craniofacial specialist.
** J August Richards (''{{Series/Angel}}'') plays a younger version of Dr. Webber.
* HeyItsThatVoice:
** In the Japanese dub: [[Creator/KotonoMitsuishi Meredith Grey is]] ''Anime/SailorMoon'', [[Anime/ExcelSaga Excel]] and [[Anime/NeonGenesisEvangelion Misato Katsuragi]]; [[MieSonozaki Caroline Grey is]] [[VideoGame/StreetFighterIV Crimson Viper]] and [[{{Naruto}} Yugito Nii]]; [[Creator/YukoKobayashi Arizona Robins is]] [[TenchiMuyo Washuu]].
** In the original American, a guest star shows up in the third episode. Most of us won't recognize him until we hear [[Franchise/MassEffect Admiral Anderson]], [[{{Halo}} The Arbiter]] and/or [[{{WesternAnimation/Gargoyles}} Goliath]] speak. Yep, it's KeithDavid.
* IKnewIt: Before season 9 even aired, everyone was saying that the return of [[spoiler: Richard's wife Adele]] [[BackForTheDead would be her last]].
* NamesTheSame: Mark Sloan shares a name with ''another'' TV doctor, Creator/DickVanDyke's character on ''Series/DiagnosisMurder''.
* WhatCouldHaveBeen: Ellen Pompeo revealed that the producers wanted to couple Meredith with Burke, and that Isaiah Washington's disappointment after this idea was scrapped contributed to off-screen tension (that eventually ended up getting him fired).
* WordOfGod: All of the female characters are versions of or parts of Shonda Rhimes' personality, according to her.
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