Winehouse steps into the spotlight during the 46664 concert honoring Nelson Mandela in London. Plus: Rihanna & Adam Levine, Blake Lively, Mary-Kate Olsen and more

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Rihanna leans on Maroon 5 singer Adam Levine Wednesday during their visit to MTV's Hollywood studios, where the duo taped a performance of their duet, "If I Never See Your Face Again," for Pete Wentz's new show, FNMTV.