The long-term personal lawyer of US President Donald Trump, Michael D. Cohen, has admitted privately paying an adult film star US$130,000 in 2016.
It follows US media reports that the actress known as Stormy Daniels was paid to sign an agreement stopping her discussing an alleged affair.
She first said she had a relationship with Mr. Trump in a 2011 interview.
The lawyer has previously said Mr. Trump vehemently denies it occurred.
In a statement to The New York Times, Mr. Cohen said neither the Trump Organisation nor the Trump campaign was a party to the transaction with Ms. Clifford.
He added that neither reimbursed him for the payment, either directly or indirectly.
Mr. Cohen said he told the Federal Election Commission the same after a watchdog group filed a complaint about the payment serving as an in-kind political contribution to Mr. Trump's campaign.
He stressed that the payment to Ms. Clifford was lawful, and was not a campaign contribution or a campaign expenditure by anyone.
In a 2011 interview with InTouch magazine, the actress said she began a sexual relationship with Mr. Trump in 2006, shortly after Melania Trump gave birth to his son Barron.