Justin Bartha's real-life wedding seemed to go down without a hitch!

The star of "The Hangover" over the wed fitness trainer Lia Smith in her native state of Hawaii on Saturday.

The pair walked down the aisle in front of famous friends including Reese Witherspoon and hubby Jim Toth, Bartha's "Hangover" co-star Ken Jeong and actor Jesse Eisenberg, according to People magazine.

After a sunset ceremony on Oahu Saturday, guests partied at a reception at Kualoa Ranch.

"They were sweet together and looked very in love," a source told Us Weekly. "He was holding her bouquet for her and walked with his arm around her after the vows. She had a big smile on her face and nuzzled her face up to his neck."

Bartha, 35, and Smith announced their engagement in May.