(CBS) Jonah Hill looks very different than he did a year ago.
The actor showed off a super-slim physique when he appeared at MTV Video Music Awards (the photo on the left is from Sunday's ceremony, and the one on the right is from a March 2010 event).
Last month, Hill, 27, told the Los Angeles Times that he was unsure of how much weight he had lost.
He said he had begun working out and changing his eating habits because he "thought it was important to be healthier."
"It's not fun," he added. "I wouldn't say it's the most fun endeavor I've ever took on in my life -- but it's important. And I'm enjoying it. If I eat something unhealthy now, I kind of feel a little weird and my body hurts."
Hill appears next in the baseball flick "Moneyball," alongside Brad Pitt. The film hits theaters on Sept. 23.