Red carpet wedding: Justin Bartha and Lia Smith

The Hangover alum and personal fitness trainer exchanged vows in Oahu, Hawaii on Jan. 4, and were feted by Reese Witherspoon, her husband (and Bartha's agent) Jim Toth, and Jesse Eisenberg. "They were sweet together and looked very in love," an onlooker told Us. Us exclusively confirmed Smith was pregnant at the time, and the pair welcomed their first child, a baby girl, three months later in April.