Wilmer Valderrama and Kevin Federline were spotted partying together in Las Vegas over the weekend, and the two hit it off so well K-Fed invited Fez to collaborate with him on his next album.

The new BFFs "chilled out together and insisted on rapping along to every song played ... K-Fed invited Wilmer to be involved with his next album." Britney's baby-daddy even had a nifty new trick to foil the paparazzi at Heineken's Thirst Studio Global Sessions. "He had a ...