Britney Spears is striking back. The pop singer and new mom, who has been the subject of rampant tabloid speculation over the state of her marriage to husband Kevin Federline, filed a $20 million libel lawsuit on Monday against Us Weekly magazine. The suit has nothing to do with the recent avalanche of stories questioning her marriage, though -- it's over a report that she and Federline made a sex tape and were worried that it would be leaked.

According to an Associated Press report, the suit seeks $10 million in libel damages and $10 million for misappropriating Spears' name and image to promote sales of the glossy weekly tabloid. It also asks for unspecified punitive damages. The suit cites an item in the October 17 issue of the magazine's "Hot Stuff" section under the headline "Brit & Kev: Secret Sex Tape? New parents have a new worry: racy footage from 2004," that claimed Spears and Federline were worried about a former member of their entourage releasing a steamy sex tape, which they reviewed with their estate planning lawyers.

The article said that Spears had given the tape to lawyers on September 30 and that she and Federline were "acting goofy the whole time" while watching it.

"There was no laughter, disgust or goofy behavior while watching the video in the company of lawyers because they did not watch any video, and because there is no such video," the lawsuit claims, according to the AP.

According to the suit, Spears went to court after Us refused her request for a retraction, saying it stood by the story.

Spokespeople for Us and Spears could not be reached for comment at press time.

Spears has been a staple of Us coverage since marrying former dancer and aspiring rapper Federline, with whom she had her first child, Sean Preston, in September. Though she gave rival People magazine access to photos of her wedding and Sean's birth (see [article id="1514457"]"Britney Baby Photos To Appear In People"[/article]), she criticized Us in February after the magazine published pictures of her October honeymoon in the Fiji Islands taken by resort staff members.

The singer wrote an open letter on her Web site to "false tabloids ... and other desperate magazines" in which she said "I'm really concerned about the people you hire to work at your companies. ... I'd like them to ask themselves the question, 'What am I lying to myself about?' Is it that you are 50 pounds overweight? ... Until you face what is going on in your life, I guess you'll remain a false tabloid."

Us hit back at Spears in a statement, reminding her that she had sold pictures of her wedding and stepdaughter to other publications. "Could it be that Britney is seeing red after not seeing the green from these photos?" Us said (see [article id="1497220"]"The Honeymoon Is All Over: Britney PO'd Over Leaked Photos"[/article]). "Britney Spears should start a magazine if she'd like to dictate her own coverage."