Kim Kardashian and Kris Humphries have signed a prenuptial agreement.

The newly engaged couple - who plan to marry later this summer - reportedly enlisted the help of Kim's mother Kris Jenner to thrash out a deal to protect each of their earnings should their marriage fail.

A source told US Weekly: "Kim's Beverly Hills home and all of her assets are protected. Additionally, she keeps anything she earns during the marriage."

Kim pocketed $10 million last year from her various endorsement deals and reality TV shows while basketball player Kris earns $3.2 million a year with the New Jersey Nets although his income is set to soar this summer when he becomes a free agent and can sign to a team of his choice.

Friends revealed the agreement is simply a precaution for the couple and say 26-year-old Kris is happy to sign to make his 30-year-old fiancee happy.

The source added: "He does not receive anything if the marriage fails. He agreed to that. He's not worried."

Kim and Kris reportedly want to marry within the next two months although Kim is hoping her big day will rival the recent British Royal Wedding.

A friend revealed: "The wedding will happen within six to eight weeks. They're doing things very, very quickly. It's being fast-tracked.

"Kim is planning the wedding of the century. She doesn't see why a royal wedding should get more attention that hers. She sees herself as a bigger celebrity than Kate Middleton."