Justin Bartha enjoys the sun and sand on New Years Day with a lady friend in Hawaii. Credit: Bruja/Juan Sharma/Anthony Goodrich, PacificCoastNews.com

Justin Bartha has a new girlfriend!

The Hangover star, 34, is dating trainer Lia Smith, a source confirms to Us Weekly.

The couple were photographed on New Year's Day together relaxing on a beach in Maui, Hawaii. Bartha met Smith, a Pilates instructor at Equinox in L.A., during a session and the twosome have been dating for a while, the source tells Us.

Smith showed off her hot beach bod in a colorful string bikini top and orange shorts while tanning with The New Normal actor.

Bartha previously dated Ashley Olsen for two years before calling it quits in March 2011.