In 2011, Hill lost about 18kg for his role in Moneyball opposite Brad Pitt on a diet of Japanese food.
The 32-year-old - who co-starred with Leonardo DiCaprio in The Wolf of Wall Street - was this week nominated for Best Actor in a Musical or Comedy at the Golden Globes for his performance in War Dogs.
But he looked almost unrecognisable underneath a black cap and sunglasses, with his figure visibly thinner.
Speaking to New York magazine, Hill previously addressed the issue of his fluctuating weight.
"Being healthier came along with maturity," Hill told the magazine in 2011.
"And it's hard, because a lot of times people want you to be the guy you were when they met you.
Jonah Hill (right) stars in the film, War Dogs.
"And I love doing funny movies, but I want to mature, literally, in how I treat myself. I'm not living in a frat house with a bong plastered to the table," Hill said, according to the Daily Mail.
"But all this stuff (body image) is just part of maturing in body and in mind. I just want to be a good man and to make my family proud. And, you know, I want to live a long time."