Britain's newest world champion David Haye insists he will relinquish his WBA and WBC cruiserweight titles to start campaigning at heavyweight.
Haye (left) has already had one fight at top weight
The 27-year-old knocked out Frenchman Jean-Marc Mormeck in Paris on Saturday and revealed he is now "95% sure" he will make the step up.
Haye told the BBC: "I'm proud of what I've achieved, but I want to go up to heavyweight and do the same thing.
"It's a very strong possibility. I'm 95% sure it's the next thing for me."
Londoner Haye admitted he had struggled to make the 200lb limit for his fight in France and added: "I'm a "natural heavyweight.
"I have had to train for 17 weeks to get down to 90kg and it is not healthy. I am skin and bones.
"The whole week leading up to the fight my legs felt hollow because of trying to make the weight.
"I had to graft in a corrugated iron gym at my training camp in northern Cyprus in ridiculous heat and I lost 30lb of muscle.
"It was a lot of sacrifice but it was worth it to be undisputed champion, but now I'm ready to move up."
Haye has already fought once at heavyweight, disposing of Tomasz Bonin in one round at Wembley last April. The Pole had previously lost just once in 38 bouts.
He paid tribute to the strength of Guadeloupe-born Mormeck, who had regained his world titles by out-pointing O'Neill Bell in a July rematch
Haye took a count after dropping to his knee in the fourth round
"He had a great chin and I landed a few shots early and he was still smiling," Haye said.
"It didn't faze him and I knew I had to break him down slowly and surely. I kept investing in body shots and connecting downstairs and eventually I could see his energy going down."
The former European champion also admitted he had to pull himself together after being floored in the fourth round.
He said: "Credit it too him, he took away my legs completely. He hit me on the temple. But it happens in boxing and we know he is a great fighter.
"I could have stayed up but I knew my legs were a bit shaky so I took a drop to knee and got my faculties together and then fought my way back into it.
"I knew I had to pace myself but I won't have to do that again because I'm going up. My legs just weren't there because of working so hard to make cruiserweight."