The former "The O.C." star, 30, revealed the news during an appearance on late night talk show "Jimmy Kimmel Live!" on Tuesday, November 30, after confessing she was feeling self-conscious about her figure in her little black dress.
Initially joking about having a beer gut, she told presenter Jimmy Kimmel, "I wanted to wear it (the dress) but I was a little nervous about wearing it tonight because it's a little tight and I'm carrying a little extra weight... I drank a lot of beer before I came here... No, I'm pregnant actually!" But Reeser admits she has "no idea" how writers behind her new U.S. superhero series "No Ordinary Family" will deal with her expanding belly on the show.
She says, "I have no idea. I mean work knows, I've told them, because my character (Katie Andrews) is really kind of not so great with men, but it is a superhero show, so it could be like a magical thing that happens! I don't know."
Reeser and Warren wed in May 2009.