Mason Thames may be leading the new How to Train Your Dragon movie — but he’s been a fan since day one.

“That was my childhood, growing up with those movies,” the 17-year-old actor tells People, reflecting on what it means to now play Hiccup in the live-action remake of the beloved animated franchise. “The fact that I get to be a part of this world and do this is insanity to me.”

Thames, best known for his breakout role in The Black Phone, admits he was completely hooked from the very first time he saw the original 2010 DreamWorks film. “I remember when I watched the first movie as a kid, there was so much wonder and magic to it. I love everything about it, especially Toothless, because he’s so cute.”

For Thames, the emotional core of the series wasn’t just the dragons — it was Hiccup himself. “Hiccup as a character, he was my hero growing up. There’s so much about him that I could relate to,” he says. “Especially my journey becoming an actor reminded me a lot of Hiccup. All he wanted was to be a Viking, and in his village they looked down on him and kind of cast him out. Once [Hiccup] accepted he was different and realized he was different, that’s where he truly became Hiccup. I related to him a lot.”

Landing the role wasn’t just a big deal — it was a full-circle moment. “That was one of the best moments of my life,” Thames recalls of the casting call from director Dean DeBlois, who also helmed the animated trilogy. After a London chemistry read, weeks passed with no word — until he got a surprise call.

“Actually, we only have one question,” DeBlois said. “Would you like to play Hiccup in our movie?”

Thames’ reaction? “I stood up. I jumped out of my chair and broke my light,” he says with a laugh. “That was a very special moment. My family, they were really proud of it.”

Taking over the role once voiced by Jay Baruchel was no small task. “They’re very big shoes to fill,” Thames says. “Hiccup — that character is my childhood. I really wanted to do the fans right. Also for myself, because I’m a fan.”

That passion helped ease his nerves. “When you care about movies so much and you hear that they’re going to be making it in a live-action format, you get kind of nervous that it’s not going to be the same, that it’s going to be soulless,” he admits. “That’s something I was worried about until I met with Dean… You should see the love he has for these characters and this world and this movie. I think it really shows in the final product.”

While the live-action reboot doesn’t aim to replace the original trilogy — which earned Oscar nods for all three of its films — Thames sees it as a celebration.

“The original movie is, in my opinion, a masterpiece,” he says. “It wasn’t a thing of what can we change or make better than the originals. It was how can we expand upon this world and expand these characters. Bringing it to a new generation in a live-action format was a lot of fun.”

And for a lifelong fan-turned-star, it couldn’t be more personal. “This film, to me, feels like a love letter to the original.”

How to Train Your Dragon, which also stars Gerard Butler, Nico Parker, and Nick Frost, is now playing in theaters.