Joseph Parker had secret double elbow surgery in December to improve his performance, the Herald can reveal.
The procedure has helped his movement and power significantly; Parker and his team believe it will be a game-changer for his fight against Anthony Joshua.
The Parker camp have been desperate to keep his operation under wraps.
Firstly for fear of upsetting the delicate and lucrative negotiations with Joshua and his promoter Eddie Hearn late last year, and secondly because the New Zealand heavyweight was eager to use it as a piece of mental warfare before the world title unification bout in Cardiff on April 1.
Parker and his promoter David Higgins will go into detail regarding the reasons for the surgery in Auckland, and the many benefits he has received from it, at a press conference in London late on Friday night.
Duco Events have given no details but have promised a revealing video at the press briefing, and that it will be very newsworthy.
Parker had complained of issues with his left elbow over the past few years, and it had apparently got to the point where he couldn't throw his trademark lightning double jab without extreme discomfort.
Take your Radio, Podcasts and Music with you