Jay-Z has adopted his pregnant wife Beyonc Knowles' diet in an effort to support her.

The 42-year-old father-to-be and Beyonc are currently expecting their first child together.

Jay-Z is making every effort to assist his wife during her transition into motherhood.

"[Jay-Z and Beyonc are maintaining a] partially vegan diet," a source told Us Weekly.

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

Beyonc has spoken before about how she is committed to eating healthy throughout her pregnancy.

"I've been really conscious [about food]," Beyonc told Katie Couric on American news programme 20/20 this month.

"I've been trying my best not to lose control."

The couple's joint effort to maintain a high level of nutrition is paying off.

Jay-Z, who is currently performing concerts in Los Angeles on his Watch the Throne tour with rapper Kanye West, took his wife out to the Spare Room club in Hollywood after his show this week.

"[Jay-Z and Beyonc were] dancing up a storm," an eyewitness told the magazine.

"They were loved up and sweet together [and] partied until 4 a.m.!"

Jay-Z and Beyonc will welcome their newborn in early 2012.