The world has known for years she's not that innocent, but Britney Spears (search) announced on Tuesday she's also a little knocked up.

The pop tart apparently pulled an April Fool's joke on her fans and the "false tabloids" she denounced as "liars" earlier this month: Spears and her ex-background dancer husband, Kevin Federline (search), are expecting their first child.

" " the couple gushed in a posting on Spears' Web site.

The couple have been dodging rumors their marriage was in trouble and that Spears was pregnant. The twosome defiantly announced they would star in a UPN reality show that would showcase their "personal love story," allowing their fans a peek at "what really happened" rather than the distortions of the press.