Credit: Kevin Winter/Getty Images

Twilight Saga star Kellan Lutz is jealous of his most famous costar Robert Pattinson. "He's such a talented motherf*****," Lutz, 24, told New York's Daily News Tuesday. "I wonder how I can get what he has."

But the jealousy is mutual, Lutz says.

"He asks me what I do to work out because he wants man boobs like me," the buff star (and Calvin Klein underwear model) says.

"I just tell him I like doing pushups."

Last year, Lutz told Us Weekly that he tried to help Pattinson bulk up with a supply of Muscle Milk and Isopure protein shakes. Pattinson, 23, wasn't a fan of the potions.

"Rob was like 'How do you drink this stuff?!"

Pattinson's rumored love and costar Kristen Stewart has also taken jabs at his lack of athleticism. "Rob can barely jump rope," she told Harper's Bazaar last fall. "I call him Flippy because when he does his stunt rehearsals, he flips around," she said, imitating a penguin's walk. "And God, when he tries to run..."