Beyoncé Knowles was back on the set of her music video in LA yesterday. Beyoncé changed into a sexy yellow number that showed off her legs after topping off her outfit with a crown on Tuesday. It's been a while since she put out music, but Beyoncé and Michelle Obama teamed up for a youth fitness initiative by releasing a "Single Ladies" remix and a catchy, fun dance to go along with it. While on the West Coast, Beyoncé missed out on pal Gwyneth Paltrow's cookbook launch party in NYC. Both women's husbands, Jay-Z and Chris Martin, were on hand to celebrate with Paltrow, who's been making the rounds to promote her latest endeavor. Jay-Z has his own new project, the lifestyle site Life + Times, and to kick it off he exchanged interviews with Gwyneth on her GOOP newsletter.