Melania Trump has demanded Hunter Biden "retract the false, defamatory, and lewd" statements he made about her that referenced her relationship with Jeffrey Epstein, according to Fox News.
Lawyers for the first lady of the United States said if Mr Biden fails to retract his statements, she will seek over $US1 billion ($1.5 billion) in damages.
The notice letter has been sent to Mr Biden and his lawyers, and states that failure to comply will see Ms Trump pursue "remedies available to her to recover the overwhelming financial and reputational harm that you have caused her to suffer".
The statements were made in a YouTube interview Mr Biden did on Channel 5 with Andrew Callaghan's broadcast titled Hunter Biden Returns.
In the interview, Mr Biden also launched a scathing attack against George Clooney and said his father's poor showing during the US presidential debate in 2024 was due to taking Ambien.
Alejandro Brito, a lawyer serving as litigation counsel, alleged in the notice that there were two defamatory comments made.
Those comments were:
a. "Epstein introduced Melania to Trump. The connections are, like, so wide and deep."
b. "Jeffrey Epstein introduced Melania, that's how Melania and the First Lady and the President met. Really? Epstein made the intro? Yeah, according to Michael Wolff."
The notice gave Mr Biden until August 7, 2025, to respond or comply, saying "you are on notice".
A source close to the matter told Fox News Digital the former US president's son did not comply with the requests.
'Trading on the names of others'
In the issue notice, Mr Brito said Mr Biden has a "vast history of trading on the names of others — including your surname — for your personal benefit".
"The above-referenced false, defamatory, malicious, disparaging, and inflammatory statements were published to deliberately denigrate Mrs Trump," the notice said.
"The timing of this video is evident and underscores the actual malice behind the decision to publish it given the plain falsity of the statements.
"It is obvious that you published these false and defamatory statements about Mrs Trump to draw attention to yourself."
As well as asking for "a full and fair retraction of the video", Ms Trump's lawyers want Mr Biden to apologise.
The letter claims Mr Biden's "source" for the statements was "serial fabulist Michael Wolff" — a journalist who has had work published in The Daily Beast.
His article titled Melania Trump 'Very Involved' in Epstein Scandal was the target of a separate cease and desist letter from Ms Trump's legal team.
Mr Brito said "following receipt of our cease-and-desist demand letter just a week ago, The Daily Beast issued an apology to Mrs Trump and retracted the false and defamatory statements contained in the Article by deleting it in its entirety".
Ms Trump's lawyers say that means Mr Biden has "unjustifiably relied upon Mr Wolff's false, defamatory, disparaging, and inflammatory statements about Mrs Trump and maliciously elected to republish them".
Communications director for Ms Trump, Nick Clemens, told Fox News that she is going after anyone who makes similar claims about her and Epstein.
"First Lady Melania Trump's attorneys are actively ensuring immediate retractions and apologies by those who spread malicious, defamatory falsehoods," he said.