Adult-film actress Stormy Daniels has sued President Donald Trump, alleging he never signed a nondisclosure agreement to keep her quiet about an "intimate" relationship between them.
- Ms Clifford's attorney says the agreement was signed days before the election
- Donald Trump's attorney says he paid Ms Clifford $US130,000 of his own money in 2016
- In the "hush agreement" Donald Trump was referred to as David Dennison
Mr Trump has denied having an affair with Daniels.
Stormy Daniels, whose real name is Stephanie Clifford, filed the lawsuit in Los Angeles, claiming the agreement is invalid and she is free to publicly discuss her relationship with Mr Trump.
The lawsuit, which Clifford's attorney, Michael Avenatti, published in a tweet, says she signed both the agreement and a side letter using her stage name on October 28, 2016, days before the 2016 US presidential election.
Mr Trump's attorney, Michael Cohen, signed the document the same day, but Mr Trump never signed the document, the lawsuit claims.
The "hush agreement", as it is called in the lawsuit, refers to Donald Trump as David Dennison and Stephanie Clifford as Peggy Peterson.
The side letter agreement reveals the true identities of the parties as Clifford and Mr Trump, according to the lawsuit.
Clifford asks in the lawsuit for the Los Angeles County Superior Court to declare the agreement and side agreement invalid and unenforceable.
The White House did not immediately respond to a request for comment.
Mr Avenatti was also not immediately available for comment.
According to the lawsuit, Clifford and Mr Trump had an intimate relationship that lasted from the summer of 2006 well into 2007, including meetings in Lake Tahoe and at the Beverly Hills Hotel.
Clifford was quoted in a 2011 interview with In Touch Weekly magazine that she had an affair with Mr Trump after they met at a Lake Tahoe golf tournament in 2006, not long after Mr Trump's wife, Melania, had given birth to their son, Barron.
Mr Cohen has said he paid Clifford $US130,000 of his own money in 2016, the year Mr Trump was elected president, but said neither the Trump Organisation nor Mr Trump's campaign was a party to the transaction, though he declined to say publicly what it was for.
The lawsuit said the 2016 hush agreement called for $US130,000 to be paid into the trust account of Ms Clifford's then-attorney.
In return, Clifford was not to disclose any confidential information about Mr Trump.
The suit alleges Mr Cohen had tried to keep Clifford from talking about the relationship as recently as February 27, 2018.
"The attempts to intimidate Clifford into silence and 'shut her up' in order to 'protect Mr Trump' continue unabated," the lawsuit said.