1. Stacey Dash in 'Clueless'
One of the most famous examples of an old teen in a movie, Stacey Dash was 28 when she played 17-year-old Dionne in Clueless. Blessed with youthful good looks, Dash reprised the role for the TV series and continued to play a high schooler until she was 33.



2. Trevor Donovan in '90210'
No doubt about it, Trevor Donovan is a stud on 90210, but does it really make sense to bring in a 30-year-old to play high schooler Teddy Montgomery? The actor was just a month shy of his 31st birthday when he made his first appearance on the show in 2009.



3. Leonardo DiCaprio in 'Catch Me if You Can'
When you're watching Catch Me If You Can, it's easy to forget Frank Abagnale was 16 and 17 through the course of the movie. Sure, part of that is his grown-up confidence and the adult nature of his various scams and crimes, but it's also because Leonardo DiCaprio was 28 when the movie came out.



4. Gabrielle Carteris in 'Beverly Hills: 90210'
Children of the '90s will remember the original 90210's resident fogey. Gabrielle Carteis was 29 when she played high school newspaper editor Andrea Zuckerman, making her about 32 when she finally graduated.



5. Taylor Kitsch in 'Friday Night Lights'
Taylor Kitsch is about 10 years older than his Friday Night Lights counterpart Tim Riggins. He was 27 when the running back graduated from high school, but in the show's first season it was a little weird to have a full-grown hunk playing a 14-year-old.



6. Minka Kelly in 'Friday Night Lights'
Minka Kelly is a year older than her Friday Night Lights romantic interest, Taylor Kitsch. She was 26 when the show began, making her 11 years older than her on-screen counterpart.



7. Barbra Streisand in 'Yentl'
The age of Yentl's title character is kept vague in the movie, but Barbra Streisand was 41 when she played the teen girl who enters Yeshiva school dressed as a man to follow in her father's footsteps. Even if the character was supposed to be 20, that's still a 21-year age gap.



8. Charisma Carpenter in 'Buffy the Vampire Slayer'
Charisma Carpenter was 27 when she started playing Cordelia Chase on the first season of Buffy the Vampire Slayer, making her about 11 years older than her character.



9. Tom Welling in 'Smallville'
While it's not crazy to see a 24-year-old play 18, Tom Welling was supposed to be playing a 14-year-old version of Clark Kent when Smallville made its 2001 debut. That first episode becomes particularly absurd when the 6-foot, 3-inch Welling openly worries about starting his freshman year of high school.



10. Alan Ruck in 'Ferris Bueller's Day Off'
Alan Ruck is full of brooding pathos in the otherwise hilarious Ferris Bueller's Day Off. While his attitude is convincing as an angry high school kid, he was 30 when the movie was released, six years older than co-star Matthew Broderick.



11. Kenny Wormald in 'Footloose'
Kenny Wormald starred in the 2011 remake of Footloose, which stayed remarkably true to the original 1984 film, right down to the ages of the actors. While Wormald (who was born the year the original was released) was 27 playing 17, Kevin Bacon was 26 playing the same part.



12. Eric Christian Olsen in 'Fired Up!'
While several of the actors on this list could probably pass for their characters' ages, Eric Christian Olsen looks laughably older than the high school football player he plays in Fired Up!. He was 31, when they filmed the movie.



13. Stockard Channing in 'Grease'
Ridiculously big age gaps are nothing new in Hollywood. Stockard Channing was 34 when she played Rydell High School menace and Pink Ladies gang leader Betty Rizzo in Grease.



14. Henry Winkler in 'Happy Days'
Henry Winkler built a career on playing Fonzie on Happy Days, but the actor was already 29 when he started playing the high school drop-out. While the Happy Days timeline isn't frozen, it does move slowly, keeping Winkler a teen well into his 30s. He was 39 when the show finally ended in 1984.



15. Sean Patrick Thomas in 'Save the Last Dance'
Save the Last Dance was fraught with racial tension between romantic leads Sean Patrick Thomas and Julia Stiles, but maybe instead of focusing on their different skin colors, the movie should have addressed their age gap. While Stiles was 20 when the movie was released, Thomas was 30 and had crow's feet so obvious you can see them in the poster.



16. Michael J. Fox in 'Back to the Future: Part 3'
Michael J. Fox was 24 when he started playing 17-year-old Marty McFly in the first Back to the Future movie. But since all three movies take place within a few months of each other, the actor was 29 and still playing 17 when the third movie was released.



17. Jason Earles in 'Hannah Montana'
Sure Jason Earles looks younger than his years, but he was 29 when he started playing Miley Cyrus' teenage brother on Hannah Montana. Oddly enough, even at 30 the actor wouldn't have had much trouble passing for 15 on the show.



18. Cory Monteith in 'Glee'
Cory Monteith was 27 when the first episode of Glee aired in 2009, and he's 29 in the show's third season. Monteith's age is perhaps the reason show runner Ryan Murphy decided the kids on the show would graduate instead of letting them age on air.



19. Alison Lohman in 'Flicka'
Alison Lohman was 27 when Flicka was released, making her 11 years older than her onscreen counterpart. But, really, who would notice? The youthful actress was still baby-faced at 30. Thankfully, though, she wasn't brought back for the completely unrelated Flicka 2, which has the same plot with a different actress.



20. Tobey Maguire in 'Spider-Man'
Tobey Maguire was 26 while playing 17-year-old Peter Parker in Spider-Man. Fortunately the next two movies moved forward in time, sparing him the indignity of playing a teenage web-slinger at 32.



21. Parminder Nagra in 'Bend It Like Beckham'
Parminder Nagra played a 17-year-old soccer prodigy in Bend It Like Beckham, but at the time she was 27. Not only did it make her 10 years older than her character, it made her 10 years older than co-star Keira Knightley, who was supposed to be about the same age.



22. Robert Pattinson in the 'Twilight' Movies
Playing a vampire in a series of movies comes with its own set of problems, not the least of which is the built-in time limit of playing a character who doesn't age. While Robert Pattinson was 22 playing 17 in the first Twilight movie, he'll be 26 playing the part in the final film. Forgive us the pun, but that's getting a little long in the tooth for a teenage vampire.



23. Paul Wesley in 'Vampire Diaries'
Paul Wesley is an unfortunate victim of the same circumstances as Robert Pattinson: He keeps getting older, but his vampire character stays the same age. At the start of Vampire Diaries season 3, Paul was 29, 12 years older than his character. Some fans may find it stranger still that Ian Somerhalder (33 playing 24) is 10 years older than real-life girlfriend and co-star on the show, Nina Dobrev.