"It's funny, I talked to ['Talk' co-host Jerry O'Connell] the other day for two hours," he said. "Jerry, I can't believe that I forgot to tell you that around Christmastime we got married. Bo and I got married!"
Corbett -- who has been in a relationship with Derek, 64, since 2002 -- showed off his ring, putting it up to the camera.
"We're pretty private people, we didn't make an announcement, all our friends and family knew but this is the first time either one of us has said anything publicly about it because really we haven't had an opportunity," he told O'Connell. "So, you're my buddy and now I guess I'm telling all of America, or the world."
The "Sex and the City" star then opened up about their decision to tie the knot.
"After 20 years we decided to get married, we didn't want 2020 to be that thing that everybody looks back at and hated," he said. "We thought, 'Well, let's get one nice thing out of it.'"
Last year, Derek explained why she and Corbett hadn't gotten married yet.
"I think when you're beginning a young family and you're going to have children and set up this new family tree branch, it's obviously a wonderful commitment and it's meaningful," she told Fox News in April 2020. "But for us in our lives, it hasn't been yet."
At the time, the actress also gushed over her longtime beau (and now-husband), saying there was "just an attraction, a comfort" when the two first met.
"He makes me laugh all the time. He's full of life, full of joy. I became attracted to him and I still am. We take things day by day and I think we are still there," she said. "We're starting to get a little more settled."