Report: Kevin Federline's brother says he is father of Britney Spears' son Sean

The Many Faces of Britney Spears

While some celebs try to smile and look pretty for the camera, Britney shows us all her dimensions.

Kevin Federline’s brother is not a fan of pop superstar Britney Spears.

According to RadarOnline, Christopher Federline has launched legal action against Spears, claiming he is the “true father” of her son Sean Preston, 7. He’s also alleging that the “X Factor” judge stole his credit card and used his money to buy thousands of dollars worth of comics for her kids.

In newly filed court documents, posted on US Weekly’s website, Christopher claims he slept with the pop princess while she was married to his brother Kevin, and he fathered her eldest son.

“I do confess I slept with Britney, and I am the true father, but the public does not need to know.”

He asks for a temporary restraining order from the star, who he calls and “out of control maniac.”  

He adds that when he confronted Spears about the alleged credit card theft “she laughed at me, told me my brother Kevin ruined her life, Britney made fun of me…”

K-Fed’s brother adds that when he contacted the comics store to dispute the alleged charges made by Brit, the owner would not comply because “Britney Spears is a longtime customer.”

He specifies in the document that the purchases included issues of Archie comics, Betty Boop and Mad Magazine.

A source told RadarOnline that "Chris says the fling was a mistake. He says he always felt bad about it and kept it to himself because he didn't want Alisha, his wife at the time, to find out."

Spears was married to Kevin Federline from 2004-2006. She gave birth to Sean Preston in Sept. 2005 and had her second son with Federline, Jayden James, shortly before she filed for divorce in 2006. Kevin was granted sole physical and legal custody of the children in 2008.

Spears is currently engaged to her former agent Jason Trawick.

She was a judge on this season of "The X Factor," which wrapped last week. But sources told US Weekly and The New York Post that her job may be in jeopardy.

“Britney seemed very nervous and shy, she wasn’t able to do many press commitments, and she was a little too nice as a judge," a source told The Post. "Producers wanted drama, tears and meltdowns, but there were none."

Spears reportedly makes $15 million for her judging gig, and sources claim she won't be brought back next season for the Simon Cowell series.

Britney and Kevin’s reps did not immediately return FOX 411’s request for comment.