WireImage 1 / 23

Jay-Z is eating like a pregnant woman!

The 42-year-old dad-to-be is supporting Beyonce by dieting with her. A source tells the new Us Weekly that the duo are maintaining a "partially vegan diet."

PHOTOS: Bey's bump style

"Jay's trying to be disciplined, and he needs the energy to support her," a source adds.

Beyonce, 30, isn't going to let herself go just because she's expecting. "I've been really conscious [about food]," she told 20/20. "I've been trying my best not to lose control!"

PHOTOS: Most talked about bodies of 2011

Jay and Bey's commitment to healthy living seems to be paying off. A source tells Us that Monday night the duo were "dancing up a storm" at Hollywood's Spare Room club, following Jay's joint concert with Kanye West, Watch the Throne. "They were loved up and sweet together [and] partied until 4 a.m.!"

PHOTOS: Jay and Bey's sweetest moments

The next night, Beyonce and Jay-Z partied once again. This time, the couple hung out with Serena Williams, Kanye West and friends at another Watch the Throne afterparty.


Year in Review: Celebrity Babies of 2011

The Year in Celebrity News 2011

Year in Review: Celeb PDA 2011