Kelly Rutherford has filed for divorce from her husband, gazillionaire Daniel Giersch. Something major must have gone down, because the Gossip Girl actress is three months preggers with their second child.

Or is she? Perhaps the kid is someone else's? Maybe it's Chuck Bass'!

I really don't know, but what I do know is that Kelly cited "irreconcilable differences" on papers filed Dec. 30, while here hubby of two years filed for legal separation the same day.

This is the second marriage of Kelly's that has gone down the tubes. She was married to some other dude for, like, five months or something.

I do love the thought that the hubby is not the baby's father -- especially if it's another GG actor's. A gossip girl's dream... or this one's, anyway.