Federline, 31, and Prince, 27, had a late lunch at Mexican restaurant Casa Vega in Sherman Oaks, Calif. "She looked very pretty when she arrived for her bash," says an observer.
Federline, who sources says has lost about 30 lbs. since joining the cast of VH1's upcoming Celebrity Fit Club, "joked how it's about time he gets some proper food," according to an eyewitness.
The former Mr. Britney Spears was spotted out at Casa Vega having lunch with his girlfriend Victoria Prince and friends Nick and Drew Lachey and Vanessa Minnillo.
And as he made his exit, K-Fed looked decidedly more fit, sporting his usual baggy t-shirt/shorts combo and smiling confidently.