Danny Williams warned Roy Jones Jr. that he will "get seriously hurt" when he faces Mike Tyson.
Tyson is coming out of retirement at the age of 54 to take on Jones, 51, as the pair prepare to fight on Nov. 28 in an exhibition match.
Williams himself is 47 and lost in a one-sided defeat to MMA heavyweight Sergei Karitonov over the weekend, which prompted the British boxer to permanently retire.
He knows plenty about the fighter, having fought Tyson in 2004, winning by a surprise knockout in the fourth round.
He told the Sun of his concerns that Roy is out of his depth due to fighting out of his normal weight.
"I think Roy is going to get seriously hurt. He is a natural middleweight,” he said.
The pair are set to fight at the Dignity Health Sports Park in California towards the end of the year, and it marks Tyson’s first fight in 15 years. His last bout was in 2005 against Kevin McBride, with his most recent win two years before that against Clifford Etienne.
Tyson's return to the ring may have prompted Oscar De La Hoya to come out of his own retirement, though no fight has yet to be agreed for the Golden Boy head.
Jones, meanwhile, most recently fought in 2018, beating Scott Sigmon.