Prostitute Irma Nici has countersued David Beckham for breaking the U.S. Constitution by hampering her free speech, just days after the sport superstar's lawyer served her with a US$25 million writ for claiming the pair slept together.

Nici hit headlines around the world last month when she sensationally alleged Beckham had paid for her services on two occasions in 2007.

Beckham immediately launched legal action against Nici and In Touch magazine, which published the story, and his legal team handed her papers in New York on Monday. The writ accuses the former prostitute of causing him "great mental anguish" with allegations he hired prostitutes.

A lawyer for Nici has now filed a countersuit against Beckham, accusing him of ignoring America's strict freedom of speech laws, according to Britain's Sunday Mirror.

Attorney Paul Rolf Jensen says, "California law does not allow public figures like David Beckham to stifle free speech. Maybe he didn't live here in Los Angeles long enough to learn how precious we here consider our rights to tell the truth in print."