Timothee Chalamet had to be told to stop losing weight for his role in 'Beautiful Boy'.
The 22-year-old actor plays drug addict Nic Sheff in the biopic and shed 20lbs for scenes when his alter ego hit his lowest point but movie bosses were worried he was "pushing" himself further than he needed to.
Explaining the weight loss scenes were shot first to allow the actor to return to his regular size for the happier moments, director Felix Van Groenigen said: "It helped him physically feel it and hit some sort of rock bottom.
"I mean, he was very closely followed but at some point, we had a feeling he was pushing it further than we wanted, because he was so committed to it.
"We did have to say at some point, 'Timmy, stop. It's great. We don't want you to go into a dangerous place.' "
Timothee stars opposite Steve Carrell as his on-screen father in the movie and they struck up a bond instantly.
Steve said: "We just naturally became friends. There weren't any exercises that we needed to go through in order to generate that affection. I think we had it almost instantly."
Timothee agreed: "Yeah, I feel the same way. I felt very... just taken in.
"I felt a strong warmth from Steve and from Felix, our director, and then the scenes with Amy Ryan and Maura Tierney as well.
"I felt a very paternal quality coming from them."
While Steve had already been cast before his screen son, the 'Call Me By Your Name' actor wowed the director with his audition tape.
Felix told Total Film magazine: "We did auditions and saw a lot of tapes coming in. And at some point we saw an audition of a young actor, not very well-known - Timothee Chalamet.
"You know, he blew us away with his bold and fearless energy and how he could switch between a person completely strung out on drugs and also be this very intriguing teenager trying to find a bond with his dad.
"So at some point, we put them in the room together to do a chemistry read and I just felt it - they connected."
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