Kim Kardashian West has turned to Jessica Simpson for pregnancy advice.

The 34-year-old reality TV star is expecting her second child with her husband Kanye West and has reportedly sought advice from the blonde beauty, who has son Ace, 20 months and two-year-old daughter Maxwell with Eric Johnson, on how to control her weight while pregnant.

A source told OKMagazine.com: ''Kim has been leaning heavily on Jess for advice on staying in shape during her second pregnancy.

''Jessica had a similar experience and ballooned first time but kept it under control the second. She's proving to be a class-A mentor for Kim.''

The raven-haired beauty and the singer-turned-fashion designer are said to have ''always considered each other to be rivals'' but have bonded over their desire to shift their pregnancy pounds.

And Kanye - with whom Kim already has a 23-month-old daughter North - is said to be thrilled that his wife has made a new friend.

The insider added: ''Kanye's definitely encouraging the friendship. He sees a lot of synergy between Kim and Jess, from fashion to diets to reality shows. It's a no brainer.''