After nearly eight years of marriage, the couple decided to renew their vows in front of about 50 guests Saturday at St. Lucia's Sugar Beach Resort, People reported.
Damon and Barrosso, an Argentine-born former bartender, were married in a private, civil ceremony in December 2005, Us Weekly reported.
"They've wanted to do it for a long time," one guest of the said of the vow renewal. "They had a tiny ceremony the first time, and wanted to celebrate with family and friends."
Guests were invited to a cocktail reception on a nearby beach after the ceremony.
"This isn't a 'Hollywood' wedding," a guest told Us Weekly. "Matt wanted it to be fun, happy and private. He felt like Luciana deserves this, first and foremost."