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Lomu, the recipient of a kidney transplant, said he wasn't worried about the potential risks of entering the ring.
"There's no difference between this and playing rugby.
Life is too short to be wrapped up in cotton wool."
Broadcaster Grant Kereama, who had donated the kidney, had been informed of the decision and was supportive, Lomu said.
"I can't wait to get it on."
Lomu, who played 63 tests and two World Cups for the All Blacks, challenged Sonny Bill Williams to a fight, but the All Black midfielder's managment declined the offer.
"I respect Sonny Bill Williams, but I'd happily step into the ring with him," Lomu said.
He will fight alongside fellow former All Blacks Christian Cullen, Troy Flavell and Carlos Spencer, with current All Black Liam Messam and former New Zealand Maori player Slade McFarland also on the list.
They will take on former Australia league and rugby player Wendall Sailor, along with former Kiwis Monty Betham, Awen Guttenbeil, Joe Vagana and Jerry Seuseu and current New Zealand representative and Souths Sydney player Issac Luke.
The event, which will take place at the Trusts Stadium Arena in Waitakere, will raise money for the Prostate Cancer Foundation of New Zealand.
Lonergan said he was yet to sign a broadcaster for the event.
Each bout would consist of three two-minute rounds.
Promoter Dean Lonergan said the line-ups would be announced on November 1 but it was hoped that former Wallaby Sam Scott-Young will also be involved as former boxer Betham was keen on the match-up.