Like many actors, Mark Wahlberg takes his work very seriously. So seriously that he dropped a staggering 60 pounds to portray gambler Jim Bennett in the upcoming fictional film "The Gambler" — and he did it in a very unhealthy way.

“I went from 197 to — the lightest I’d ever been in a movie was in 'Boogie Nights,' I was 138 — so I wanted to beat that,” he recently said. “I beat it by a pound, so 137. I was losing weight while we were shooting the movie, too, so continuity kind of went out of the window.”

How did the 5-foot-8 actor manage to get down to such a low weight? By over-exercising and not eating. At one point, his lips even turned blue due to lack of nutrition.

"No energy, no nutrition, and the studio, there was a complaint about that, that my lips were always looking blue,” he said about the weight loss. “What the f–k do you want me to do? I haven’t eaten anything! If you make them red, I’m going to look weird, like I’ve got lipstick on, so it is what it is.”

The trailer for "The Giver."

The married father-of-four admits he became obsessed with the part, which required him to be "as thin as possible," according to director Rupert Wyatt.

"Once I get into it I can’t stop, so it’s a 24 hour, 7 days a week thing,” he shared at the AFI Fest premiere of the film, which hits theaters Dec. 19, in Hollywood this week. “I stopped eating food for the first six weeks and just had small liquids throughout the day, then I was exercising two or three times a day.”

Mark's certainly in good company when it comes to stars who drastically transformed for movie roles. Scroll through below to see 'em!