Christopher Federline says HE is the father of Kevin and Britney's son Sean Preston, according to a new lawsuit.

Britney's former brother-in-law, who described the X Factor mentor as a "maniac," filed the suit on December 18 seeking a restraining order against Spears.

In the papers, Christopher also claims Brit stole his credit card and racked up more than $4k in charges.

PATERNITYHOAX.jpgThe lawsuit goes on to say that Britney "told me I have a small pe***, she also blackmailed me and told me if I tell the police that she stole my credit card that she will tell the world I'm the true father of Sean Preston, not Kevin."

A judge has since dismissed the lawsuit.

Britney and Kevin's camp have yet to issue a comment.

UPDATE - It has been confirmed the lawsuit was a hoax by convicted felon Jonathan Lee Riches who also claimed to be Newton, CT shooter Adam Lanza's uncle. Riches, posing as Federline's brother Christopher filed the phony complain December 18.