The chart-topping singer hits the stage for a good cause in Las Vegas. Plus: Usher, Katie Holmes, Lauren Conrad and more

PRETTY 'YOUNG' THINGS

It's the Disney Channel clique! The Wizards of Waverly Place's Selena Gomez hangs with High School Musical sweeties Vanessa Hudgens and Zac Efron at Teen Vogue's Young Hollywood Party on Thursday at the Los Angeles County Museum of Art.