George Foreman is backing Bernard Hopkins to break his record and become boxing's oldest world champion ever.

Foreman was 45 when he beat Michael Moorer to win a version of the heavyweight crown in 1994, but Hopkins will be 46 when he challenges Jean Pascal for the WBC light-heavyweight crown on May 21 in Montreal.

Heavyweight legend Foreman has prepared himself to lose his slice of boxing history.

"I thought such a record would last a lot longer because 45 is phenomenal and just think, Bernard Hopkins is 46.

"He's probably the only one who could break such a record because not only does he possess this big punch to get a knockout, but he's also a good boxer and at times, a counter-puncher.

"He can pull it off, no doubt about it.

"If Bernard is able to win this thing and do it decisively, it's going to help boxing."

However, with Hopkins fighting in the champion's back yard - the fight is a rematch of the pair's controversial draw last year - Foreman says he will need to target a knockout victory.

"You must get a knockout," he told Hopkins during a conference call to promote the fight. "This fight and the record will not be broken on a unanimous decision. There must be a knockout.

"My hope is that he'll go out there and put on a good fight. Understand that these fights generally are not won by decisions.

"In the latter rounds he should look for a knockout like I did (against Moorer in 94). There was no way I could have been in the record books without that one-two knockout punch."

However, Foreman is predicting Hopkins will do just that and win by stoppage.

"The first fight is going to have to be erased," he added.

"The decision was not of quality. The second time around, Bernard will get a knockout."