50 Cent says he works out like a woman.

The muscular rapper says his toned physique is the result of "girly" weight-free routines rather than pumping iron.

He said: "It's intense, and there are no weights involved. And some of it's like girly stuff, like just kicking your leg, but it's muscles you don't really ever work at. Men don't usually go to the gym and say, 'I'm going to develop my a*s. This'll be the J.Lo workout.' "

As well as sharing his workout tips, the hip-hop star has also revealed a collaboration with British singer Robbie Williams is on the cards for 2009.

50 Cent said: "We attempted to do it during the 'Curtis' album. We talked about recording in Los Angeles and then the next time I spoke to him he was on his way to rehab.

"Hopefully we will have a chance to work with each other."