Jonah Hill has publicly struggled with his weight for years, undergoing a dramatic weight loss in 2011. Since his serious slim-down Hill’s weight has fluctuated, but remained on the healthier side. However, new photos of the 31-year-old on the set of his upcoming film, “Arms and the Dude,” reveal a shocking transformation.

The young actor is pictured wearing linen khaki pants, a baggy blue button down shirt and a yarmulke, all of which are believed to be a part of a costume. What isn’t known is whether the weight gain is for the role or not. In the film, Hill and fellow actor Miles Teller play two men contracted by the Pentagon to provide American allies in Afghanistan with weapons.

According to E!, the movie is based on a Rolling Stone article titled “The Stoner Arms Dealers: How Two American Kids Became Big-Time Weapon Traders.” The article, which came out in 2011, was written by Guy Lawson. The film is being directed by Todd Phillips, who previously worked on “The Hangover” and “Old School.”

Hill's size has been fluctuating since he first hit the big screen in 2007. The star made a name for himself after appearing alongside Michael Cera in “Superbad.” After landing a few more major roles he was cast in 2011’s “Money Ball.” That’s when he got serious about shedding a few pant sizes.

Hill lost 40 or more pounds, all of which he chalked up to growing up. The actor claimed he simply wanted to mature as an actor and in the way he treated himself, so he began eating better and working out.

“Being healthier came along with maturity,” he told Vulture. “And it’s hard, because a lot of times people want you to be the guy you were when they met you. And I love doing funny movies, but I want to mature, literally, in how I treat myself.”