A polygraph test taken by adult film star Stormy Daniels in 2011 has concluded she was "truthful" in saying she had an affair with Donald Trump.
The lie test, obtained by CBS News, said she had unprotected sex with Mr Trump in 2006.
Mr Trump married Melania Trump in 2005 and "vehemently denies" the affair.
The president's lawyers are seeking $20 million (£14m) from the actress, saying she broke a non-disclosure deal, which she claims is invalid.
She first made claims of a sexual relationship with Mr Trump in a 2011 interview with InTouch magazine, and the lie test was taken for Life & Style magazine but never before released.
Polygraph tests are inadmissible in court as evidence in many US states.
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A copy of the confidential report said Stephanie Clifford, which is the legal name of Ms Daniels, took the polygraph examination on 19 May 2011.
The test, analysed by a computer algorithm, was developed in a physics laboratory at Johns Hopkins University.
According to the polygraph examination, Ms Clifford responded "yes" to the following questions:
- Around July 2006, did you have vaginal intercourse with Donald Trump?
- Around July 2006 did you have unprotected sex with Donald Trump?
- Did Trump say you would get on The Apprentice?
The test concluded that Ms Clifford "is truthful about having unprotected vaginal intercourse with Donald Trump in July 2006".
Ms Clifford said in a pre-test interview to polygraph examiner Ronald D Slay that she and Mr Trump first had sexual intercourse at a golf event in Lake Tahoe, California.
However, the polygraph data was inconclusive about whether the former television star promised Ms Clifford a spot on "The Apprentice".
The test examiner wrote of Ms Clifford that "there were no observable indications of intent to deceive".
Ms Clifford is currently suing Mr Trump and his lawyer, Michael Cohen.
Mr Cohen has said he paid Ms Clifford $130,000 out of his own money to remain silent.