Justin Bartha, the next on the seemingly endless list of celebrities tying the knot this January, marries trainer girlfriend Lia Smith in a blissful ceremony in Hawaii on Saturday, Jan. 4.

"The Hangover" star and Lia Smith exchanged vows in a private affair in Hawaii attended by celebrities pals Reese Witherspoon and partner Jim Toth. Toth is also Justin Bartha's agent.

"Lia wore a white dress with thin spaghetti straps and jeweled sandals," one of the people who attended the ceremony shared in an interview. "Justin wore a dark colored suit and burgundy socks. They were sweet together and looked very in love." 

The insider shared a few more details about the ceremoney, saying Bartha held he bride's bouquet for her then walked with his arm around Smith after exchanging vows. The new bride sported a big smile on her face and nuzzled her face up to the actor's neck.

The source added that "their family and friends seemed so happy for them and had an incredible time hanging out in Hawaii leading up to the wedding. It was a destination wedding for all."

The wedding insider also confirmed the attendance of Hollywood A-listers Jesse Eisenberg ad Ken Jeong in the unique ceremony which was performed at a historic fishing pond on an altar made out of sticks. 

The ceremony started around 4 in the afternoon and went on for only 15 minutes before the newlyweds and their guests went to a nearby ranch for the reception.

The 35-year-old actor and his trainer girlfriend got engaged back in May of 2013 during their couple getaway at Post Ranch Inn in Big Sur, Calif.  
"They're the cutest couple. She was completely surprised by the whole thing," a source close to the couple shared in an interview. "The trip to Big Sur, the engagement, the ring, everything. So cute."

"The Hangover" star reportedly proposed to Smith with a diamond ring that is "just unbelivable," adding that the pair "are an amazing couple" and looked "so gorgeous together."

Justine Bartha and his new wife first went public with their relationship after being photographed together in a beach resort in Maui, Hawaii on New Year's last 2013.