Buzzfeed.com has a list of actors who played teenagers . . . convincingly or not . . . in movies and on TV, when they were a lot older than that in real life. Here's what they came up with:
1. Tom Welling was 24 when he played a 14-year-old Clark Kent on "Smallville".
2. Rachel McAdams was 27 when she played a high school student in "Mean Girls".
3. Henry Winkler was 29 when he played a 17-year-old Fonz on "Happy Days".
4. Anna Kendrick was 27 when she played a college freshman in "Pitch Perfect".
5. Ben McKenzie was 28 when he played a high school kid on "The O.C.".
6. Gabrielle Carteris was 31 when she played a 16-year-old on "Beverly Hills, 90210".
7. Teddy Montgomery was 31 when he played a 17-year-old on "90210".
8. Antwon Tanner was 30 when he played a 17-year-old on "One Tree Hill".
9. Andie McPhee was 29 when she played a 14-year-old on "Dawson's Creek".
10. Gabrielle Union was 28 when she played a high school cheerleader in "Bring It On". Her co-star Kirsten Dunst was 18.
11. Scott Porter was 27 when he started playing a high school quarterback on "Friday Night Lights".
(Buzzfeed.com has corresponding pictures for all of these. And if you scroll down to the bottom you'll also see high school photos for Johnny Depp, Robert Downey Jr., Snoop Dogg, Rashida Jones, and Beyoncé.)