(Cover) - EN Showbiz - Mark Wahlberg's muscles are so big one of his co-stars couldn't concentrate around him.

The Hollywood hunk appears in the movie Pain and Gain, which also stars Rebel Wilson.

Mark has been sporting a hulking physique for the film, which is about a pair of body builders.

The sight of his rippling pecs was almost too much for Rebel to cope with.

"It's kind of like I can't concentrate," she laughed to E! Online. "I keep just going, Uh, uh, uh,' and being like really embarrassing whenever I'm around him.

"He's super nice. Like he drove me back to my trailer the other day."

Rebel also appears in the new movie What to Expect When You're Expecting, which follows several couples who are having babies.

The film has an all-star cast including Jennifer Lopez, Cameron Diaz, Elizabeth Banks and Anna Kendrick. Rebel was particularly fond of working with Jennifer.

"Me and Jennifer dated for two minutes," she deadpanned. "Not many people know that - but it happened. I'm not pregnant from that experience." (C) Cover Media