Bianca Lawson in 'Pretty Little Liars: t is obvious that the 45-year-old actress has aged incredibly well and hasn't changed much since 'Saved By The Bell.
Luke Perry in 'Beverly Hills, 90210: Teen idol Luke Perry will forever be Dylan McKay to his fans. The actor, who gained popularity due to his role in the teen series 'Beverly Hills.
Rachel McAdams in 'Mean Girls: Rachel McAdams was already 26 years old when she played Regina George in 'Mean Girls' (2004), a character that still haunts her to this day.
Stacey Dash in 'Clueless: Stacey Dash played the 15-year-old Dionne Davenport in 'Clueless' (1995) but was 28 in real life.
Leonardo DiCaprio in 'Catch Me If You Can: Hollywood's chameleon portrayed 16-year-old Frank Abagnale in 'Catch Me If You Can.
Matt Damon in 'Behind the Candelabra: Matt Damon impersonated the 17-year-old Scott Thorson in 'Behind the Candelabra' (2013) but was way older than his character.
Shirley Henderson in 'Harry Potter: Moaning Myrtle was only 14 years old in 'Harry Potter and the Chamber of Secrets' but was played by the then 36-year-old actress Shirley Henderson.
Gabrielle Union in 'Bring It On: Gabrielle Union is best known for her role in 'Bring It On,' where she played a high school cheerleader at the age of 27.
Ian Somerhalder in 'The Vampire Diaries: When he started playing forever-17-year-old Damon Salvatore on 'The Vampire Diaries,' Somerhalder was in reality 31.
Gabrielle Carteris in 'Beverly Hills, 90210: Sixteen-year-old Andrea Zuckerman of the teen show 'Beverly Hills, 90210' was played by Gabrielle Carteris.