Is ASHLEE SIMPSON really pregnant, or is it just a rumor? Her FALL OUT BOY fiancé PETE WENTZ goes on the defense.

"There is a witch hunt for people to be pregnant whenever they get engaged in Hollywood," Wentz wrote to MTV News Monday, as reported by People.com. "This is all news to me. I can't wait for the story about how I'm really in a gay relationship and this is all just a cover ... I mean really, this is crazy ... I mean, we're engaged, that's true, and happy about it."

Regarding pregnancy rumors, a spokesperson for the couple told ET yesterday, "We are thrilled to confirm their engagement and congratulate this happy couple. Beyond that there is nothing to add."

Ashlee, 23, and Pete, 28, announced their engagement last week and have been romantically linked since fall of 2006.