Alexis Denisof has revealed that he and Alyson Hannigan are formally engaged.

"I'm the luckiest guy in the world right now," announced Denisof during an interview at The WB's winter press preview. "Sorry. She's mine. All mine! Ha ha ha ha!"

Alexis said he decided to propose while the two took a break from production for the holidays. "We were driving up to my family in Seattle during the Christmas break from our shows... So I had the ring with me... It was burning a hole in the ... armrest of my car, where it was locked...

"We drove all night from L.A... so we could spend the following day in Napa Valley. And we were just having the most perfect day. We stopped at a winery, and... got some beautiful food to make a picnic, and then we drove up to a mountain lake. And it was there that I asked her. And lucky for me, she said yes."

The couple have set a tentative September or October date for the nuptials, which will likely take place in California.