Hughie Fury insists he has already won his biggest fight before facing Joseph Parker for his WBO world heavyweight title on Saturday.
The English boxer has recovered from a skin disease called acne conglobata, which left him too tired to train and fearing his career was finished.
"That's all behind me now," Fury told ESPN. "I've got a clean sheet, I feel a different person and a lot stronger. My body wasn't allowing me to do a lot before.
"It would put me out for two weeks at a time before the fight which was three or four weeks away. I just had to stop because I was worse off for training. I had a skin condition which was poisoning my blood and over the years it has got worse and worse."
Identifying and resolving the condition, as well as a lower back injury which forced the first scheduled fight with Parker to to be postponed, means Fury has not fought for 17 months.
But Fury -- cousin of former lineal world heavyweight champion Tyson Fury -- insists he feels like a new fighter ahead of facing New Zealander Parker at the Manchester Arena.
"I've had it for years, before my professional and amateur careers and it was difficult to live with. It put my immune system down. I saw people going forward and I was just going backwards because of it.
"It was horrific. I would try a shirt on and it would be covered in blood and every time I sparred my T-shirt would be soaked with blood.
"I've had it sorted for a year now. I took medication [Roacutane] for six months and it's just gone now. I've been able to build up muscle and body weight. People don't know what I can do because I've not been fully fit before like I am [now]."
The fight was originally scheduled to take place in Auckland, New Zealand, on May 6 but was postponed in April after Fury suffered a lower back injury.
Since recovering from the back injury sustained, Fury (20-0, 10 KOs) has been based at an isolated training camp in the Lake District, using a converted squash court as a gym. His training regime has included fell running, chopping wood and swimming in Lake Windermere.
"I've done the whole training camp outside in the Lake District and it has been a brutal, hard, blood, sweat and tears," said Fury, who turned 23 six days before Saturday's fight.
"[It's] One of the hardest training camps I've had. The hard work and torture I've been through means the fight will be the easy part."
Fury will start as underdog in his home city against Parker, but he is not concerned about the being odds against him.
"It doesn't really bother me because I feel like the champion anyway so it's a matter time and I will prove that on September 23," said Fury.
"Joseph Parker is a tough fighter and I do rate him as one of the toughest fighters out there, he's very hungry. He's got good movement and fast hands and he can box either way."
But Fury, who at 6-foot-4 is two inches taller than the champion, will enter the ring on Saturday irked by Parker's discussions with other British boxers -- world No. 1 Anthony Joshua [IBF and WBA world champion] and Tony Bellew -- about future fights.
"He was obviously overlooking me," said Fury. "That's the worst thing he could ever do and he will see that on September 23. Eddie Hearn is a cockroach.
"They'll see what they are going to get by overlooking me. I hope he's well prepared, that's for sure. This is the best you will see from me. I've had the best camp in my life and I believe it will bring the best out of me. I'm the fittest I've ever felt."