The Music and Lyrics star embraces her pet cause in Malibu. Plus: Britney, Jen & Sheryl, Taylor and more

15 of 17

B-DAY BLOWOUT

Also in Vegas, Paris Hilton gets her 26th birthday party off to a groovin' start with on-again boyfriend Stavros Niarchos at the Hard Rock Hotel & Casino's Body English nightclub on Saturday. Later, the heiress and her posse (including little sis Nicky and her beau David Katzenberg) took the festivities from the dance floor to the bowling alley.