Mike Tyson said he was fit and ready for his Nov. 15 fight against Jake Paul as the two boxers had a joint news conference in New York City on Sunday.
The match was originally scheduled for July 20 but was postponed after former heavyweight champion Tyson, 58, had an ulcer flare-up that forced some resting time.
"Iron Mike," who has a 50-6 record with 44 knockouts, was one of the most feared heavyweights in history but has not fought a professional fight since 2005.
When asked why he returned to the ring so long after retirement, Tyson's response was clear: "Because I can. Who else can do it but me? We have a YouTuber fighting the greatest fighter ever to live.
"He may have been in the ring with people who have the same intentions, but the actuality, no.
"As soon as I catch this guy it's going to be totally over, he is going to run. He is gonna run like a thief."
Paul, who was booed and heckled by the crowd, claimed he would put Tyson to sleep.
"I am here to make $40 million and knock out a legend," Paul said.
"I love Mike and I respect him but we are not friends anymore until Nov. 15," he said.
When asked if he was afraid of being in the ring with Paul, Tyson replied sarcastically: "I am terrified."
YouTuber-turned-boxer Paul, 27, is 31 years his junior and has a 10-1 boxing record.
The fight will be streamed live globally on Netflix and will take place at the 80,000-seat AT&T Stadium in Arlington, Texas, home of the Dallas Cowboys.