Actor Robert Pattinson buffed up for the Breaking Dawn installment in the vampire film series Twilight with the help of fitness fanatic co-star and model Kellan Lutz.

Fans of the film and book series will likely remember rumors of Pattinson using a body double in the film, as his previously lean physique appeared significantly more toned and muscular.  However, as MTV reports, Lutz has refuted the rumors, praising Pattinson by saying,

“Someone asked if that was me. Is that Kellan’s back? I’m really proud of Rob for working out and really training really hard. He cycled so hard and trained very hard, and he’s really diligent. He talked to me about what proteins to drink and what to do and he listened and cared. He had a great mentality for it.”

Pattinson’s rumored girlfriend, Kristen Stewart has been spotted lately attending yoga classes in Los Angeles, CA.

Perhaps the couple are getting in-shape for each other???