LOS ANGELES (AP) _ Britney Spears has filed a $20 million libel lawsuit against Us Weekly, charging the celebrity magazine published a false story reporting she and husband Kevin Federline had made a sex tape and were worried about its release.

The lawsuit, filed Monday, seeks $10 million in libel damages and $10 million for misappropriating the 24-year-old pop singer's name and image to promote sales. It also seeks unspecified punitive damages.

``We have a very credible source and we stand by our story,'' Us Weekly spokesman Alex Dudley said Tuesday in a statement.

According to the lawsuit, the article was published Oct. 17 in the magazine's ``Hot Stuff'' column and claimed that Spears and Federline feared the release of a secret sex tape, which they had viewed with their estate planning lawyers.

The article stated that Spears gave a copy of the tape to the lawyers on Sept. 30 and that she and her husband were ``acting goofy the whole time'' while watching the video.

``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 stated.

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

Spears and Us Weekly also tangled in February after the magazine published pictures of her October honeymoon in the Fiji Islands.

She issued a statement criticizing the magazine for publishing photos taken by resort staff members. Us Weekly responded with its own statement saying Spears had sold pictures of her wedding and stepdaughter to publications.

``Could it be that Britney is seeing red after not seeing the green from these photos?'' Us Weekly asked. ``Britney Spears should start a magazine if she'd like to dictate her own coverage.''