Story highlights
- Jonah Hill is showing off a slimmer figure
- The actor had some help from a celebrity friend
(CNN)Jonah Hill's new bod might be the biggest surprise of the summer.
The actor stepped out over the weekend looking almost unrecognizable.
Photos: Celebrity transformations
Photos: Celebrity transformations
Macaulay Culkin's new look is winning rave reviews from fans. The actor was spotted in July having gained weight and cut his hair. The child star, seen on the left in 2014, looked so gaunt in 2012 there was speculation he was on drugs - which he denied.
Hide Caption
1 of 23
Photos: Celebrity transformations
Jonah Hill fans immediately noticed the actor's new summer bod for 2017 and applauded his fit overhaul as inspiring. Hill credited his recent slim down to advice from "21 Jump Street" co-star Channing Tatum.
Hide Caption
2 of 23
Photos: Celebrity transformations
"Girls" star Lena Dunham showed off a slimmer physique in March on the red carpet for the opening of celebrity fitness trainer Tracy Anderson's new studio in New York City.
Hide Caption
3 of 23
Photos: Celebrity transformations
Talk show host Wendy Williams lost 50 lbs over three years and said in February 2017 that she is keeping the weight off.
Hide Caption
4 of 23
Photos: Celebrity transformations
Lil' Kim, left, at a 2003 BET event, has stirred controversy over her changing appearance in the past, but these days she's unrecognizable -- and people are talking.
Hide Caption
5 of 23
Photos: Celebrity transformations
If you know Chris Hemsworth as the mighty Thor -- at left in 2011 -- his diminished size and scraggly face for the upcoming film "In the Heart of the Sea" might come as a shock. Hemsworth tweeted the photo on the right Sunday. "Just tried a new diet/training program called 'Lost At Sea.' Wouldn't recommend it," he wrote.
Hide Caption
6 of 23
Photos: Celebrity transformations
"Roseanne" star John Goodman is known for his burly frame in addition to his acting chops. Goodman has slimmed down noticeably, as was evident at a screening of "Trumbo" in October. The photo on the left was snapped just a year earlier at a showing of "The Gambler."
Hide Caption
7 of 23
Photos: Celebrity transformations
Shonda Rhimes, creator and producer of such hit shows as "Grey's Anatomy," "Scandal" and "How to Get Away with Murder," has undergone quite a transformation. She credits diet and exercise for her loss of more than 100 pounds.
Hide Caption
8 of 23
Photos: Celebrity transformations
Melissa McCarthy has been shedding weight, and she told Gayle King on "CBS This Morning" that she simply stopped stressing over it. "I feel amazing ... and I finally said, 'Oh, for God's sake, stop worrying about it,' and it may be the best thing I've ever done," she said.
Hide Caption
9 of 23
Photos: Celebrity transformations
Filmmaker Kevin Smith in 2008, left, and in 2015. The director of "Clerks" and other movies tweeted last June that he has lost 85 pounds. His secret? Walking 5 miles every day and giving up sugary drinks.
Hide Caption
10 of 23
Photos: Celebrity transformations
Matthew Lewis, who starred as the shy and unassuming Neville Longbottom in the "Harry Potter" movies, has grown into a strapping young man. He buffed up for roles as a soldier in "Bluestone 42" and an athlete in "Me Before You."
Hide Caption
11 of 23
Photos: Celebrity transformations
Penn Jillette told People magazine there was no magic involved in his weight loss from 330 to 225 pounds. The performer, who is half of the illusionist act Penn & Teller, just changed his eating habits to shed 105 pounds and get his high blood pressure under control.
Hide Caption
12 of 23
Photos: Celebrity transformations
Oh baby you! Rapper/DJ Biz Markie celebrated his 51st birthday in better health on April 8 after shedding 140 pounds. He was diagnosed with type 2 diabetes a few years ago and said he changed his diet and shaped up in an attempt to get off of some of his diabetes medications.
Hide Caption
13 of 23
Photos: Celebrity transformations
Singer Sam Smith is looking svelte these days (at left, arriving at an event March 14) and has credited nutritionist and author Amelia Freer with helping him change his diet and look.
Hide Caption
14 of 23
Photos: Celebrity transformations
Actress Uma Thurman had some doing double-takes at the premiere for "The Slap" on Monday, February 9. The actress, 44, plays a TV writer in the U.S. update of the Australian show.
Hide Caption
15 of 23
Photos: Celebrity transformations
The transformation of Zach Galifianakis continued January 25 at the Screen Actors Guild Awards, where the actor was barely recognizable from years past. What a difference some pounds and some facial hair can make. He first started slimming down in 2013, when he decided to stop drinking.
Hide Caption
16 of 23
Photos: Celebrity transformations
Kirstie Alley set out to lose 30 pounds in 2014, but she went above and beyond and lost 50. Alley, a paid spokeswoman for Jenny Craig, used the weight loss program to slim down over the past year. Although her size has fluctuated in the past, Alley assured "Today's" Matt Lauer on January 5 that "This time, it's different."
Hide Caption
17 of 23
Photos: Celebrity transformations
When Renee Zellweger arrived at the 2014 Elle Women in Hollywood awards October 20, some people said they couldn't recognize her. Perhaps that's because the "Bridget Jones" star has spent less time in the public eye recently; her last film credit was in 2010. That should change soon: Zellweger's next film, "The Whole Truth," is due in 2015.
Hide Caption
18 of 23
Photos: Celebrity transformations
Hip-hop artist Missy Elliott proved she can still work it as she flaunted a slimmed-down figure in October at the launch of designer Alexander Wang's line for H&M. Apparently, an autoimmune disorder is not slowing down the "supa dupa fly" producer, who tweeted a picture of herself in a workout cap that reads "You Can't Workout With Us" after performing at the runway show.
Hide Caption
19 of 23
Photos: Celebrity transformations
"#RichKids of Beverly Hills" star E.J. Johnson lost 50 pounds in five weeks after undergoing gastric sleeve surgery. In September, he told People he is not setting a specific number in terms of his goal for weight loss.
Hide Caption
20 of 23
Photos: Celebrity transformations
Tom Arnold has lost about 90 pounds since his first child was born in 2013, and he was looking quite thin at the 2014 South by Southwest festival. He'd actually lost the same amount of weight before but regained it when he didn't maintain healthier habits. After his son was born, he knew he needed to make a lasting change. "I saw that little baby, and I thought, 'I gotta stay alive for as long as possible,' " Arnold said. "That's a lifelong commitment."
Hide Caption
21 of 23
Photos: Celebrity transformations
Jessica Simpson showed off a supersvelte look in a Weight Watchers ad released in February 2014. "I was so insecure -- I couldn't even believe what I weighed," Simpson told "Good Morning America." The singer/fashion mogul says she is feeling better than ever since giving birth to her second child.
Hide Caption
22 of 23
Photos: Celebrity transformations
Christina Aguilera turned heads on the American Music Awards' red carpet for two years in a row. At the awards ceremony in 2013, Aguilera surprised onlookers by arriving in a skin-tight white gown with revealing cutouts, displaying a much different look than her voluptuous appearance at the 2012 event.
Hide Caption
23 of 23
Hill's followers immediately began commenting on social media that his fit overhaul was inspiring.
"Jonah hill is weight loss goals.. bruuuh," one user wrote.
"My motivation for weight loss is skinny Jonah Hill," tweeted another Hill fan.
Hill's weight has fluctuated over the years. He gained 40 pounds for his role in the 2015 film "War Dogs."
Hill credits his recent slim down to some advice from his pal and "21 Jump Street" co-star, Channing Tatum.
"I wanted to get in better shape, so I called Channing Tatum and said, 'Hey, if I ate less and go to a trainer, will I get in better shape?'" Hill said during an interview on "The Tonight Show." "Yes, you dumb mother****er, of course you will. It's the simplest thing in the entire world."
Clearly, it worked!
