Caught in the Act!
House star Jennifer Morrison, celebrating her 29th birthday in Sin City with 15 pals including Prison Break's Amaury Nolasco, at the Hard Rock Hotel & Casino. After dining at Ago, the group took the festivities to Body English, where Morrison was brought on stage and serenaded with "Happy Birthday" by the entire club.
John Mayer, having a guys' night out with two buddies at Villa in West Hollywood. The trio began the evening lounging over quiet conversation in a reserved booth, but got louder and more animated as they enjoyed rounds of shots as the night wore on.
Kristin Cavallari, hosting Aura Nightclub in the Bahamas' first anniversary party. The former reality TV star-turned-actress was joined by Hilary Duff, sharing cocktails and dancing the night away in the club's Round Room while taking turns snapping photos with fans throughout the night.
Scrubs star Sarah Chalke, casually dressed in a halter sundress, shopping at Fred Segal in West Hollywood. She was sans engagement ring, but not to worry – the actress's rep says she's still engaged to longtime boyfriend Jamie Afifi. Despite the 90º weather, Chalke purchased a pair of jeans and a black zip-up hoodie.
By JEN GARCIA and LISA INGRASSIA
Monday's Couples Watch >