By Bronwyn Barnes
Updated Sep 21, 2011 @ 6:31 pm
Charlize Theron, Leighton Meester
Credit: Dave Allocca/Startraksphoto

Leighton Meester (in Marios Schwab) and Charlize Theron (in Chloe) helped celebrate the launch of the Rhyme smartphone during the HTC Serves Up NYC event, held at the Highline Stages in New York City. After posing for photos, the duo staked out a VIP booth while fellow guests Olivia Wilde and Elizabeth Olsen stayed mobile on the dance floor. Click through to see Rose Byrne, Lea Michele and more stars at last night's hottest parties!