How old these 26 actors really were when they played high school students.

Olivia Newton-John in Grease. Image: Paramount Pictures.

Grease was released in 1978 and became an overnight hit with our golden gal, Olivia Newton-John garnering international acclaim playing the role of sweet high schooler, Sandy. While her character was supposed to be an 18-year-old senior, Newton-John was actually 29 at the time and did a very convincing job of playing a fresh-faced teen.

Stockard Channing in Grease. Image: Paramount Pictures.

Elsewhere in the Grease cast there was an even bigger difference in age between character and actor with Stockard Channing. The gutsy, straight-talking performance of 18-year-old Rizzo came from a place of experience — at that point Channing was 34 years old and a well-seasoned Hollywood actor.

Shay Mitchell in Pretty Little Liars. Image: ABC.

When the cameras started rolling on the teen drama series Pretty Little Liars, Shay Mitchell played the role of Emily, a 16-year-old teenager. Across the seven seasons, the characters in PLL went searching for clues but it didn't take a detective to figure out why Mitchell didn't exactly look like your average teenager — she was 30 at the time.

Bianca Lawson in Pretty Little Liars. Image: ABC.

Another Pretty Little Liars cast member who did a great job of making us believe she was a legitimate teen playing a teen was Biance Lawson, who stepped into the role of Maya St. Germain. In the script she's a 16-year-old high schooler but IRL Lawson was 31 years old while filming.

Henry Winkler on Happy Days. Image: ABC.

Even if you weren't born when Happy Days first broadcast in the '70s, chances are you caught re-runs on the telly after school. For some reason, the character of Fonzie seems to be universally known regardless of which generation you grew up in. The iconic high schooler was played by Henry Winkler, who was actually 29 at the time — maybe the five-o-clock shadow should have given it away?

Keiko Agena in Gilmore Girls. Image: Warner Brothers Television.

Keiko Agena played the girl-next-door's best friend, Lane Kim, in the smash hit TV series Gilmore Girls. The sweet and studious daughter of immigrant parents was a 16-year-old high school student, but in reality Agena was 27 when she filmed the series.

Friday Night Lights cast. Image: NBC.

It's hard to narrow this one down to just one cast member of Friday Night Lights because they were literally all extremely beautiful, fit and full-grown adults. Minka Kelly was 26, Taylor Kitsch was 25, Zach Gilford was 24 and both Adrianne Palicki and Gaius were 23. The only actor to truly fit the age brief was Aimee Teegarden who was 15 years old when she played high schooler Julie Taylor.

 Ross Butler, 13 Reasons Why.

Ross Butler in 13 Reasons Why. Image: Netflix.

How do you get an audience to believe a character is a buff, high school jock? Cast a 27-year-old as a 16-year-old of course! Actor Ross Butler was well into his 20s when he playing the role of Zach Dempsey in the Netflix teen drama series, 13 Reasons Why. 

Shirley Henderson in Harry Potter. Image: Warner Brothers Pictures.

Look, we get it — some people just have a baby face that allows them to portray characters much young than their biological years. But we might need to look into what sorcery is going on with Shirley Henderson's genes because she convincingly played the role of (ghost) 14-year-old high schooler Moaning Myrtle in the Harry Potter movies when she was 36. Some witchcraft at play, indeed.

Gabrielle Carteris in Beverly Hills 90210. Image: Fox Network.

We're not sure if it was the exclusively librarian wardrobe or the mum-of-two haircut but we probably all had an inkling that actor Gabrielle Carteris wasn't really 16 during the filming of Beverly Hills 90210. Playing the iconic role of Andrea Suzkerman, Carteris was actually 29.

Cole Sprouse in Riverdale. Image: Netflix.

Having been in the industry since he was a youngster, Cole Sprouse probably knows a thing or two about how Hollywood works. When he stepped into the role of Jughead Jones on the Netflix series Riverdale, Sprouse very convincingly looked like a 16-year-old despite being 24. However, when the show ended in 2023, he was 30 years old and probably very ready to stop cosplaying as a teenager.

Gabrielle Union in Bring It On. Image: Universal Pictures.

If you stay closely tuned to Gabrille Union's social media accounts, you would be well aware that at 51 years old, she could probably still play a high schooler today. Which is most likely why, when Bring It On was released 24 years ago, we had no issue in believing the then-28-year-old was high-school cheerleader Isis.

Paul Wesley and Ian Somerhalder, The Vampire Diaries.

Paul Wesley and Ian Somerhalder in The Vampire Diaries. Image: The CW.

Alright, now this one is going to be a little trickier to wrap your head around. In the series The Vampire Diaries, we were to believe that actors Paul Wesley and Ian Somerhalder were 17-year-old high schoolers, when IRL they were 27 and 31, respectively. However, you could argue that their characters, Stefan and Damon, were actually 171- and 178-year-old vampires so technically, they weren't acting down.

Rachel McAdams in Mean Girls. Image: Paramount Pictures.

You can see why Regina George was idolised at North Shore High — she wasn't your run-of-the-mill teenager. Chiefly because she was played by then-27-year-old actress Rachel McAdams in the smash hit movie Mean Girls. She was perfectly cast but ya know, a reminder that nothing in Hollywood is real.

Stacey Dash in Clueless. Image: Paramount Pictures.

Playing a ditzy high schooler still trying to figure out their place in the world is no easy feat. Especially when you you're actually 27, as Stacey Dash was when she stepped into the immaculately styled shoes of Dionne in Clueless.

Jason Earles in Hannah Montana. Image: Disney Channel.

Yep, 29-year-old Jason Earles was cast as the 17-year-old brother of Hannah Montana on the Disney series of the same name. Those cargo pants and floppy fringe weren't fooling anyone.

Selma Blair in Cruel Intentions. Image: Columbia Pictures.

We can't think of a more perfect casting choice for innocent ingenue Cecile Caldwell in the film Cruel Intentions. And it's for this reason producers decided to overlook the age gap between Selma Blair (then 27) and Cecile, who was meant to be 17.

Meredith Monroe in Dawson's Creek. Image: The WB Television Network.

Sweet, young Andie McPhee was a pivotal member of the extended Dawson's Creek cast, and was a role made for actress Meredith Monroe. In the beloved teen drama, Andie was a 15-year-old girl; in reality, Monroe was 29 at the time of filming. 

Darren Barnet in Never Have I Ever. Image: Netflix.

Darren Barnet is the poster child sticking to the hard graft until it all pays off. He didn't get his big break in Hollywood until he was cast in Mindy Kaling's Netflix series Never Have I Ever at the age of 29. In the show he played 17-year-old Paxton Hall-Yoshida — yes a bit of a stretch but ultimately he was the guy for the job.

Alexa Demie in Euphoria. Image: HBO.

Alexa Demie's age has always caused a bit of a stir amongst the public with rumours doing the rounds a few years ago that she was actually a bit older than she marketed herself. When she first started playing the role of 17-year-old Maddy in Euphoria, Demie was reportedly 29.

Cory Monteith in Glee. Image: Fox.

It's hard to imagine anyone else in the world playing Finn in Glee other than Cory Monteith, so we're simply not going to entertain the thought. Cast in the role of the gentle giant, Monteith was 27 when he first stepped into the lettered jacket of Finn, 16.