Lennox Lewis believes Anthony Joshua and Deontay Wilder will regret not fighting each other for the rest of their lives if they fail to agree terms for a massive unification showdown.

The former unified heavyweight champion, who is the last man to hold the Undisputed Champion title, has warned both Joshua and Wilder to make their fight happen.

However the former champion, who will sit down to discuss his illustrious career for the first time at an intimate, moderated event in September, did welcome the recent speculation that Tyson Fury is prepared to fight Wilder, perhaps as soon as November.

Lewis had one obstacle during his own remarkable career and he failed to secure a fight with Riddick Bowe, who was a champion at the same time. Bowe had lost to Lewis in the Olympic final in 1988 and their rematch as professionals was on and off for nearly a decade.

The 52-year-old will relive his glory days at the O2 in London in September and will share with fans some of the secrets that have been buried since he retired in 2004.