Keeping Up With the Kardashians
Keeping Up With the Kardashians stars Kim Kardashian, Kourtney Kardashian, Khloé Kardashian and Kris Jenner Reuters

Kim Kardashian is reportedly jealous of Khloe Kardashian's slim and trim frame. Kanye West's wife apparently wants to get back into shape.

A source told Hollywood Life: "Kim and Khloe have a very competitive relationship. Kim was always the queen bee: the prettiest, the most popular and always getting the hottest guys."

"It drove Khloe crazy with jealousy growing up. But now, people are gushing over Khloe and how AMAZING she looks. She has worked so incredibly hard on her physique and her look and she's getting noticed — a lot. All the praise and attention Khloe is getting is really getting Kim irritated. She's obviously totally happy for Khloe and supportive but it is a bit much when people say Khloe's got the best body in the family now," the insider added.

The source went on: "Kim is planning on upping her workout efforts and focusing on her diet even more. It's been hard with everything that's happened in the past few months and raising two little ones, but she's rededicating herself."

Meanwhile, Khloe had previously told Cosmopolitan Australia, that the weight loss was the result of her healthy eating habits and dedicated work out.

"I've definitely become obsessed with working out!" Khloe said. "It's funny, because my weight has always fluctuated – but recently so many people have been saying 'you look so good, you've lost all this weight.' It's actually been about a year and a half that I've been making a lifestyle change.

"There's no quick fix, I would say. If I ate better, I would lose weight faster, but I don't want to. I love food and there's lots of family time with food and your friends. I work out really hard so I can have my champagne and that part of life. I'd rather take longer to lose weight, but have fun doing it," she added.