Kanye West wants his girlfriend Kim Kardashian to lose weight.

The "Mercy" rapper is said to have urged the reality TV star - who is famous for her curvy figure - to slim down and shed up to 20 pounds. Kanye thinks his good friend Beyonce - who gave birth to her first child Blue Ivy last January - has a better body than his girlfriend of six months and is encouraging her to follow the singer's grueling Dreamgirls diet, according to OK!.

"He even suggested Kim drop 20 pounds, arguing that Beyonce has a similar shape and she proved you can get that supermodel body using her lemon juice, cayenne pepper and maple syrup diet. He says he wants her to be the face of his clothing line... but to do that she has to fit into the clothes. It's really uncomfortable - her shape is what made her name. He has a long-term fantasy of turning them into the new Beyonce and Jay-Z power couple, but getting Kim to starve isn't the way to do it," a source close to the couple said.

Kanye recently got Kim to ditch her trashy style and start taking fashion tips from Britain's Duchess Kate Middleton after buying her an entire new wardrobe of more conservative designer clothes. "Kanye has been urging Kim to tone down her make-up and style her hair in a more conservative style, like Kate. And it's not just Kate's regal look that Kanye wants Kim to mimic. He's also told her that she could learn a thing or two about poise and sophistication from Kate," a close friend said.