Lennox Lewis, a boxing hall of famer has termed "ridiculous", the fight between Floyd Mayweather and Conor McGregor scheduled for August.

Lewis, who is a former world heavyweight champion, said the outcome of the fight has been predetermined.

He added that the combination of Mayweather's boxing experience and hand speed will be too much to handle for McGregor.

"It's ridiculous to me," Lewis told US sports broadcaster ESPN. "You are talking about one discipline where you can use only your hands and only a few can do it.

"Every battle sport always starts with your hands, but they are two totally different sports."

The fight is being held in the T-Mobile Arena in Las Vegas and promoters are hoping to make millions off the pay-per-view sales. Scheduled as a 12-round boxing match with 10 ounce gloves, three-time world heavyweight champion Lewis says it won't go the distance.

"I can't take it serious," Lewis said. "Mayweather is the best in his weight class, no one can touch him in boxing.

"Floyd will stop him. He's just too good at boxing for McGregor and McGregor is just too inexperienced.

"I wouldn't buy it -- but I would be interested in the result. To me, I know who is going to win already so there's no use in watching it."

Lewis, who fought for Canada at the 1984 Los Angeles Olympics, joins a growing list of boxing purists who have come out against the much-discussed fight which will take place August 26.

The 40-year-old Mayweather has been retired since beating Andre Berto in September 2015 and improving his career record to 49-0.

The matchup with McGregor gives Mayweather a chance to reach the 50-0 career milestone.