Jennifer Lopez may be working on a track with DJ megastar Tiësto. J.Lo was overheard asking to meet the DJ as she and boyfriend Casper Smart partied at the opening of the 80,000-square- foot Asian restaurant Hakkasan in the MGM Grand Hotel & Casino in Las Vegas. Tiësto headed over to her table, where he was overheard talking with J.Lo about “possible collaborations.” The lavish bash was also attended by Vanessa Hudgens, Pharrell Williams and Paris Hilton.