Hunk has been sharing his fitness tips with Twilight co-star

Robert Pattinson wants to beef up, according to his Twilight co-star.

Kellan Lutz shows off his hot body in Calvin Klein Underwear ads and R-Pattz wants the look.

Robert asks me what I do to work out because he wants man boobs like me,’ says Kellan.

‘I just tell him I like doing push-ups.’

But the 24-year-old – who plays Emmett Cullen – says he’s envious of Robert, too – for his acting and musical abilities.

‘He’s such a talented motherf*****,’ Kellan tells the New York’s Daily News. ‘I wonder how I can get what he has.’

Last month, Robert, 23, confirmed he is dating Twilight co-star Kristen Stewart, 19.  

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