Jonah Hill Seen Extra Svelte on Set of New Flick With Kristen Wiig

Jonah Hill was snapped hard at work Monday ... with a new slimmed-down look!

One of America's favorite funny guys was spotted sporting a shaggy hairdo and svelte figure while calling the shots on the set of his upcoming movie, "Cut Off," costarring Kristen Wiig.

The hilarious duo play a pair of rich twins who get cut off from their parents. Jonah, who cowrote the film, is also directing.

This isn't the first time we've seen a different version of JH ... something he's been open about through his career.

During a 2017 interview on "The Tonight Show," Jonah told Jimmy Fallon ... "I called Channing Tatum and said, 'Hey, if I eat less and go to a trainer, will I get in good shape?' and he's like, 'Yeah, you dumb motherf***er, of course you will. It's the simplest thing in the entire world.'"

In an effort to help other people in the same struggle, Jonah published a zine called Inner Children where he vented about grappling with his body image.

JH told Ellen DeGeneres in 2019 ... "I think everybody has a version of themselves -- I call it a snapshot -- you're trying to hide from the world ... Even if you get success, you grow up, or become good-looking -- you carry some part of that with you. For me, it's being this 14-year-old kid -- being overweight, wanting to fit in with these skaters and hip-hop kids, and just feeling lonely and not understanding my own worth."