Alex Rodriguez and Cameron Diaz partied at the new Cosmopolitan Hotel in Vegas for the grand opening of the Tao Group’s mega nightclub and dayclub Marquee where Jay-Z and Coldplay put on an unbelievable concert. Beyonce, Kanye West and John Mayer also took the stage and performed in front of a-list crowd including Gwyneth Paltrow, Jeremy Piven, Ellen Pompeo, Kirsten Dunst, Whitney Port, Channing Tatum and others. Celebs were seen wearing the Wear Your Music guitar string bracelet which are bracelets crafted from artists guitar strings and sold for charity, as VIP all- access passes for the weekend’s festivities. www.wearyourmusic.org