Photo: Axelle/Bauer-Griffin/FilmMagic

Hilarie Burton and Jeffrey Dean Morgan

Hilarie Burtonis loving the person her son is becoming.

TheWalking Deadactress shared a photo of Gus with his hair slicked in an Elvis-like fashion and a varsity-style jacket with skinny jeans and black boots on Instagram.

“Seventh grade won’t know what hit em!#firstdayofschool,” Burton captioned the shot, where the 12-year-old had his hands together as though he was clapping as he laughed.

The night prior, Burton shared an Instagram carousel of photos and videos, reflecting on her son’s love of both the film and Elvis Presley himself.

“Our son starts 7th grade tomorrow. And here he is, watching @elvismovie for the 12th time (no joke!), tears in his eyes,” she wrote.

Never miss a story — sign up forPEOPLE’s free daily newsletterto stay up-to-date on the best of what PEOPLE has to offer, from juicy celebrity news to compelling human interest stories.

“We’ve cried pretty much every viewing. I’m gonna need everyone to tell @bazluhrmann how much I love him for making this movie,” she wrote. “Gus went through a massive Elvis phase when he was 6. We listened to @sxmelvisradio every day. Obviously, his hair and wardrobe were influenced.”

Burton — who is also mom to daughter George Virginia, 4 — went on to share that Gus once “was brave enough to get up in front of the school with his raspy little voice and sing #foolsrushin. It was little kid fandom.”

Speaking of his love for the film, Burton added, “Gus wants to be a director. He studies this movie for its soundtrack and artistry and that very specific @bazluhrmann trademark of extravagance and heartbreak. He takes the story of Elvis so seriously. I love how he analyzes all of it.”

Jeffrey dean morgan/ instagram

Jeffrey dean morgan and son

Last fall, Gus made his acting debut onThe Walking Deadas a young walker, making him the third member of the family to appear on the AMC series.

Ahead of the episode, titled “Out of the Ashes,” Jeffrey Dean Morgan shared a sweet post onInstagramin honor of his son, which featured photos of Gus in his full zombie makeup.

“My dude. Me,@hilarieburtonand George THATS MY BOY!! We are super proud of Gusy Dean,” Morgan wrote. “Thanks to@amcthewalkingdeadand@gnicoterofor making a dream come true… a damn hoot! Xxjd”

source: people.com