Jessica Simpson DUH, I'M PREGNANT

10/31/2011 1:25 PM PDT

Jessica Simpson -- DUH, I'M PREGNANT

Jessica Simpson has finally confirmed what everyone already knew ... she's pregnant.

The singer just tweeted, "It's true ... I"m going to be a mummy!" -- posting a pic of herself in a mummy costume ... holding her baby bump.


1:45 PM -- Sources close to Jessica tell us ... her big announcement crashed her website after more than 1 million people tried to access it less than a minute after she posted the news.