In movies and television shows, an actress often tends to look younger than the age her character is supposed to be. When the character is middle-aged or older, this is a case of Hollywood Old. A character can be "supposed to be" a certain age in two ways: Either an age is stated outright in the story, or the character is a historical person.
Hollywood Old activates in three slightly different ways.
The actress is far younger than the character is at any point in the story.
The character starts out in an age bracket appropriate for the actress. However, as the years go by (or are skipped by time travel, whether in universe or in the meta sense) and the character ages, hardly anything is done to make the actress look older.
The actress and the character are technically the same age, but the actress looks much younger because of Botox, plastic surgery et cetera. The character is a real woman who looked her age or a fictional character inhabiting a time, place, or economic situation in which such things aren't available.
In Dan in Real Life 24 year old Emily Blunt plays Ruthie Draper who's supposed to be 40ish. (Her age is never specified but she went to Highschool with Mitch and Dan who's ages are also not stated but Dan has a 17 year old daughter and played by Steve Carrel so it's safe to say the characters are in at least their 40's}. Ruthie has had a lot of plastic surgery on her herself being a plastic surgeon.
Sara Dane: At the beginning of the movie, Sara is 18. The actress looks the part. However, the movie spans most of Sara's life, without the actress ever showing any signs of aging. Halfway through the movie, she has drifted into Hollywood Old territory. and at the end she even has children who look older than she does.
The Aviator: A classic type 2. Leonardo DiCaprio is right for only the first few scenes, then looks way too young during the rest of the movie. Makes it look as if everything accomplished by the middle-aged Howard Hughes was actually accomplished by a man still in his 20s.
In Superman Returns, Lois Lane was the mother of a 5-year-old and was experienced and established enough in her career to have won a Pulitzer Prize. She was played by then-22-year-old Kate Bosworth.
However, Scrooge may not be as old as most adaptations show him to be. He is usually played by actors in their late sixties (or made-up to look so), but if the woman Scrooge once courted had a teenager and an infant at the time when Jacob Marley died, which was seven years prior to the story's present, then Scrooge is probably somewhere around 50, maybe a few years older.
Speaking of Belle, in the 1951 and 1984 films, both her past and present ages were played by the same actresses.
Anyway, Albert Finney did an excellent job of playing the mid-50s Hercule Poirot, when he himself was in his mid-30s, in Murder on the Orient Express. It took the help of some make-up, but Finney is a very good actor.
Likewise, in ACT's annual stage production, the laundress and charwoman, who are middle-aged, are often played by younger actresses. The late John Gilbert, the original Scrooge in the production, started playing the role at age 37.
In the Watchmen movie, Matthew Goode was about 27 or 28 when he was filmed as 45/46-year-old Adrian Veidt/Ozymandias. Possibly justified, as Veidt's age in the film is never given, and he's meant to be preternaturally youthful-looking anyway.
It wasn't that bad. Ron and Malfoy were very obviously balding and probably looked older than they were supposed to look as a result.
The scene was originally filmed with the actors in hideous old age makeup that made them look closer to 70. Everyone agreed that the subtler approach was better.
It should be noted that the one who hits this trope hardest is Hermione, since at least Ginny had crows feet and a few lines. Hermione just put her hair up in a bun. Presumably because Emma Watson is a model and models can't look ugly ever, where Bonnie Wright isn't a model nor had she done much if anything else outside being Ginny, and thus it's ok to make her look older.
Remember, people, the characters are only in their mid-thirties. It's not like they were all supposed to be playing folks in their 'fifties'' or anything! People who keep up their health and fitness can still look young even into said fifties...
In The Sound of Music, a then-35-year-old Christopher Plummer played Captain Von Trapp, who was actually in his 50s at the time the movie was set.
Guy Pearce appears with a quite unconvincing makeup job to play the very aged Peter Weyland in Prometheus. Footage of Weyland as a young man had been shot, but was cut from the film and only appears on its website.
In Queen of the Damned, forty-year-old Paul McGann plays David Talbot, a character who's supposed to be quite old. At one point he says he's "too old to live forever" and it comes across a bit strangely, particularly if you know the line was written for someone who's actually old.
In the film version of Mortal Instruments series, 36-year-old Luke Garroway is played by 29-year-old Aidan Turner.
Oddly averted in Forrest Gump, where Sally Field actually does look the appropriate age for her character of Forrest's mother. However, if you look at pictures of her in real life, she's actually quite attractive for someone in her 60's.
Another Sally Field aversion: The Amazing Spider-Man. Sure, as Aunt May, she doesn't look quite as old as the May from the comics, but in comparison with Field's own real-life looks, there's still a brutal difference.
In one episode of Star Trek: The Next Generation, Captain Picard is reunited with a woman he dated 20 or so years ago (Note, if this post refers to the first season episode, "We'll Always Have Paris," the woman is played by Michelle Phillips, who was in her early 40s and only 4 years younger than Patrick Stewart, so the pairing is both likely and age-appropriate). The woman looks like she's 25, as a result of 24th century medical science. Similarly, "The Survivors" features 67-year-old John Anderson playing 85-year-old Kevin Uxbridge and 55-year-old Anne Haney playing 82-year-old Rishon Uxbridge (that said, the Uxbridge's given ages might be false because Kevin is really a powerful energy being and Rishon is an illusion). The pilot has 67-year-old DeForest Kelley playing 137-year-old Admiral McCoy (although he does look pretty withered).
In the episode "The Pegasus", Terry O'Quinn plays Commander Riker's former CO, Admiral (formerly Captain) Pressman. Pressman is, presumably, 15-20 years older than Riker, but Terry O'Quinn, who plays Pressman, is barely a month older than Jonathan Frakes.
Captain Picard himself was consistently described in the original series bible as a man of about mid fifties in age. This age was given precisely so that he would not be an Action Hero type captian, and would therefore act like a real starship captain relegating all of the action stuff to a younger first officer (in an attempt to address a common criticism of the original series depiction of Captain Kirk). The Star Trek Encyclopedia by Mike Okuda gives Picard's birth year as 2206. Being that the first TNG episode is set in 2363 or 2364 means that Picard is about 12 years older than Patrick Stewart was at the time he began playing the role. Stewart was only 45 at the time but Picard started as about age 58. The Star Trek Universe has already established that humans remain in their prime a bit longer.
Of course, given that Patrick Stewart looks almost exactly the same over two decades later, it was probably appropriate that he be aged up a bit.
In the Doctor Who episode "The Girl in the Fireplace", (adult) Reinette looks exactly the same no matter what year she's shown in. Except when she's a child.
In season seven, a big deal is made out of the Ponds moving on with their lives and aging every time the Doctor comes back to see them (they mention having traveled with The Doctor for 10 years). The problem with that second bit? Not one bit of effort is made to make Arthur Darvill and Karen Gillan look like anything other than extremely attractive people in their early thirties.
Although considering Amy was maybe nineteen in her first episode and about twenty-one during season five, "early thirties" arguably is them aging and moving on with their lives.
In season one of the old Doctor Who, the First Doctor has an Accidental Marriage to a woman we find in what's sort of an Aztec retirement village. The actress is younger than the one playing the Doctor's granddaughter. You'd think they could at least get a woman over thirty to play a woman over sixty.
The first two Doctors were played by younger actors playing older (well, of course they're playing older, but we mean in terms of the Doctor's apparent age), taking their portrayal of the Doctor to the top of what they could pass for. The First Doctor was played by a 55-year-old as someone in his late 60s or early 70s, the Second Doctor by a man of 46 as someone in his early 60s. Both made use of age makeup, notably the First Doctor's wig. Most of the others played it their age or slightly younger (Tom Baker took the role at 40 and played it like he was in his early 30s until he visibly aged too much to carry on doing that, and Matt Smith, 27 at debut, played it like he was in his late teens). This can be uncomfortable at times - how could Peter Capaldi and William Hartnell be the same age at their debut? How is Christopher Eccleston only one year older at debut than Tom Baker, and only five years younger than Patrick Troughton? How can it be that Peter Davison is only two years older than Matt Smith? It very much annoys the crowd who like to complain that the Doctor is far too Younger and Hipper.
This is pretty subjective, all told. Some viewers think that Tom Baker looked much older than 40, especially considering that Colin Baker was the same age when he was cast. For that matter, Sylvester McCoy is not even a year older than Colin Baker but looks at least a decade older and played the role as a dotty old professor. Also, many fans think that Matt Smith's portrayal felt more like a very old man who now had a youthful body and enjoyed being able to move freely. In his quieter moments, however, he wore those years much more so than did David Tennant.
LOST: With all the flashbacks and flashforwards and time travel going on, the same character can be Hollywood Old and looking too young in the same episode. In later seasons this is sometimes averted by making the same character be played by different actresses (who look really similar but with a clear age difference) in different time periods. This series contain several cases of Playing Gertrude that are NOT also cases of Hollywood Old.
Happens a lot in the present-day scenes in Cold Case, particularly in episodes where the case in question took place before about 1960.
This is the 50-year-old King Henry VIII according to The Tudors. This◊ is the 50-year-old Henry VIII according to Hans Holbein the Younger.
Charles Brandon is this trope in spades. You'd never guess that Henry Cavill is supposed to be portraying a sixty-year old man during the war scenes in France. He looks young and fit until he's inexplicably given wrinkles and graying hair in the final episode.
A.N.T. Farm has a principal who is supposed to be horrifically old. She is played by a 50 year-old woman.
Suite Life On Deck has Ms. Emma Tutweiler. She is supposed to be a caricature of an old maid, worrying about being single, living with her cats, and one character remarks that she aged since high school in a very tactless fashion. This seems understandable and relatively bearable for a kids show. Except for the fact that she is played by this actress (see Erin Cardillo and for the costume, it doesn't change anything).
Hilariously and wonderfully lampshaded in Wizards of Waverly Place, when addressing the eldest son and daughter's misconceptions about age. Thirty-five doesn't equal middle age. The scene is really cathartic in a form of media which generally displays sexism and ageism in order to pander to a younger audience.
Old Lady Gibson in Fallout: New Vegas, despite her white hair, barely looks older than about 40. Then again, some people in real life get gray hair at 30 or earlier. This also applies to the older age settings for the player character (said to go up to 60), as there is no "wrinkled" face option for them outside of mods, unlike certain NPC's.
Atrus in Myst is played by the game's co-creator Rand Miller (who does double duty as Atrus' son Achenar) who was in his early thirties when he first assumed the role in the original game. Rand Miller has noted that he once felt he was too young to play the role of Atrus. But since his likeness and voice has become engrained as Atrus to Myst fans, it would have been wrong to recast the character in the sequels.