Multiple sources have confirmed the marriage to UsWeekly — and on Wednesday, former O.C. star Adam was seen leaving a boxing gym in LA with a wedding ring just visible.
Adam, 34, and Leighton, 27, only went public with their romance last February. The couple, who worked together on the 2011 film The Oranges, were originally thought to be planning to get married this summer.
"Leighton and Adam are crazy about each other and have talked about getting married eventually," a source said at the time of their engagement. "But she had no idea he would propose so soon! It was the surprise of her life and she's ecstatic!
"Right now their plan is to get married next summer. They are still deciding if they want a destination wedding or if they'll marry in southern California somewhere."
Adam has been romantically linked to his O.C. co-star Rachel Bilson and 34-year-old director Lorene Scarfaria, while Gossip Girl star Leighton previously dated Austin Powers actor Aaron Himelstein.