Christian Slater announced his engagement to girlfriend of four years Brittany Lopez during his Wednesday guest appearance on Late Night with Jimmy Fallon.
The 43-year-old Nymphomaniac star revealed that he thought Lopez was a lesbian when he first met her at Miami resort Little Palm Island in 2009.
"This girl came walking along with another lady, a slightly older lady," he told Fallon. "I was sitting in my usual spot, eating my oatmeal that morning - and this spot was famous for people proposing to each other - and the next thing I know she gets down on one knee and proposes to this older lady."
Slater said he thought he had just witnessed "a niche lesbian engagement." He went to wish the women congratulations but as he approached them he realized it was Lopez trying to help her aunt "capture the beauty and the romance of the moment."
"She was making a joke, and I witnessed it, and it intrigued me, and the next thing I know we were hanging out in the Everglades," he added.
The marriage will be the second for Slater. He divorced journalist and television producer Ryan Haddon in 2007. Together they had two children: 13-year-old Jaden, 13 and 11-year-old Eliana.
The Interview with a Vampire actor will star in the 2013 Lars von Trier-directed and written drama Nymphomaniac alongside Charlotte Gainsbourg, Stellan Skarsgard, Shia LaBeouf, Stacy Martin and Jamie Bell.