Finn Wolfhard was the only one Weird stuff child to start at the exact age of his character.
Note: The actors’ birthdays/ages are from IMDb and Wikipedia unless otherwise linked, so take these with a grain of salt!
Weird stuff star Finn Wolfhard was 12 when he first started filming as Mike for Weird stuff. His character would also be 12.
Euphoria star Alexa Demie is reportedly 31. Her character is now 18.
Dylan Sprayberry was 15 when he started filming for teenage wolf. His character, Liam, was a freshman transfer, and although his age was never stated, 15 would be the correct age.
Shirley Henderson, who played Moaning Myrtle in the Harry Potter movies, was 37 when she first appeared in the movies. Her character died and became a ghost at age 14.
Gossip Girl star Taylor Momsen was 14 when she started playing 14-year-old Jenny.
Hannah Montana star Jason Earles was 29 when the show aired. He played Miley’s 16-year-old brother Jackson.
Buffy the Vampire Slayer star Michelle Trachtenberg was 14 when she was first introduced as Buffy’s 14-year-old sister.
Gloria Stuart was 86 when she filmed her role as 100-year-old Rose in Titanic.
Molly Ringwald was her character’s age – 16 – in The breakfast club.
Anthony Michael Hall turned 16 while filming for the same movie. His character was also around 16.
Never have I ever star Darren Barnet was 28 when he first started filming as a high school junior Paxton (so around age 16 or 17).
Kaya Scodelario was 14 when the first season of Hides broadcast. Her character, Effiy, was also around 14.
Hannah Murray was 17 when Hides started to breathe. Her character was also around 17.
Ditto for Nicholas Hoult, who played Tony.
Bianca Lawson was 30 when she shot the pilot for… Liars, playing the 16-year-old Maya.
And Cody Christian was 14 when the pilot was shot and played 14-year-old Mike.
Stockard Channing was infamously 33 when she played 17-year-old Rizzo in Fat.
And Michael Tucci was 31 when he played 18-year-old Sonny.
Dawson’s Creek star Michelle Williams was 16 when the show started filming. She played 16-year-old Jen.
This one is a bit complicated, like the timelines of Oh mom! makes no sense – but Donna can’t be older than 43 in the movie. Meryl Streep was 58 at the time of filming.
Julia Stiles was 18 then 10 things I hate about you was released, and 17 during filming – her character Kat, a high school senior, would have been around 17 or 18.
Tanya Reynolds, who plays Lily on sex education, was around 27 while filming for the first season. Her character was around 16.
When Kristen Stewart started filming twilight, she played the 17 year old Bella, she was 17. She turned 18 while shooting.
Ser’Darius Blain was 29 when he played Fridge in Jumanji: Welcome to the jungle. As a high school student, Refrigerator would have been 18 at his oldest.
Morgan Turner was 17 when she filmed her role as Martha in Jumanji: Welcome to the jungle. Since she was in college two years later, the character was probably 16 or 17 in the movie.
Michael Steger was 28 then 90210 premiere. His character, Navid, was a sophomore, so he must have been around 16.
Trevor Donovan was cast at age 30 to play Teddy (a junior in high school) in Season 2. His character is said to have been around 17.
Grant Feely, who played 10-year-old Luke in the new series Obi-Wan Kenobiis 10 years old.
Harry Shum Jr. was 27 when his first episode of cheerfulness broadcast. His character was a sophomore – so probably around 16.
Blake Cooper was 12 then the maze runner came out. His character, Chuck, would be 12 or 13.
Stacey Dash was 27 when she filmed her role as Dionne in ignorant. Her character was around 16.
Mia Sara was 18 when she played 17 or 18 year old Sloane in Ferris Bueller’s Day Off.
Alan Ruck was 29 when he played 17 or 18-year-old Cameron in the same movie.
Kirsten Dunst was 18 then Bring it on was released (and probably 17 during filming, although I can’t find the shooting dates). Her character, a high school senior, was about 17 or 18.
Timothy Granaderos Jr. was 29 when he finished season 1 of 13 reasons why. His character, Montgomery, was around 17 or 18.
Amandla Stenberg was 12 when they filmed their role as 12-year-old Rue in The hunger Games.
Ross Butler was 28 when he filmed To all the guys: PS I still love you. His character, Trevor, was about 17.
Lachlan Watson was 16 when he filmed for Chilling Adventures of Sabrina began. Their character, Theo, was probably around 16 (since Sabrina turned 16 in the first episode).
And finally, Keiko Agena was 27 when the first episode of Gilmore Girls broadcast. Her character, Lane, was 15 or 16.
Which surprised you the most? Let us know in the comments!