Evander Holyfield and Vitor Belfort came face-to-face in their press conference ahead of their fight and there was a surprise caller to the event.
The two fighting veterans will clash in the ring on Saturday night in Florida.
Belfort, a former UFC champion, was due to fight Oscar De La Hoya before the boxing legend was hospitalised with coronavirus.
Holyfield, who is 58, stepped in at the last minute on a card that also sees Anderson Silva fight Tito Ortiz and David Haye take on Joe Fournier.
The press conferences were held on Thursday night and Donald Trump called in to the event.
Trump will give ‘no holds barred’ commentary on the fight, which is taking place on September 11.
When asked if he had to fight someone on Saturday night, who would it be and what would the result be, Trump said: “If I had to pick somebody in the world, not only a professional boxer because I will take a pass at the professional boxer as that could be a dangerous subject.
“If you said if I had to box somebody, I think my easiest fight would be Joe Biden. I think he’d go down very, very quickly.
“He once said ‘oh, I’d like to take him behind the bar’. He’d be in big trouble if he ever did.
“I think Biden would go down within the first few seconds.”
Biden was the man to beat Trump in the US Presidential elections last November.
Trump controversially refused to accept the result and this led to disorder at the Capitol as his supporters stormed the building where Congress was certifying Biden’s victory.