Tyson Fury declared "yesterday is history" as he ramped up his preparations for his clash with Deontay Wilder, but could not resist another pop at domestic rival Anthony Joshua.

Fury is putting his undefeated record on the line against Wilder in Las Vegas on December 1, looking to take his opponent's WBC heavyweight belt in the process.

The bout represents the biggest of the second half of Fury's career, the 30-year-old having had over two years out of the ring due to personal problems after his memorable win over Wladimir Klitschko late in 2015.

The name of Joshua – the IBF, WBA and WBO champion – continues to hang over the fight, though, with Fury calling his fellow Englishman a "p***y" when asked to describe him in a word.

"The two best heavyweights with balls like King Kong are going to fight on December 1," he said at a media workout in Los Angeles.

"The winner is the man. Him, that other guy (Joshua) and his promoter, they had their opportunity."

Fury is training at altitude at the Big Bear camp in California as he readied himself to face Wilder, who, like Fury and Joshua, boasts an unbeaten record.

"The Tyson who beat Klitschko is dead and gone, that was years ago, I don't live on the past and just for today. What happened yesterday is history," Fury said when asked if fans would see a different Fury.

"Training at altitude has been very hard. The air is thin and it's hard to breathe. I came over here and I was already very fit, could fight 12 rounds on the pads, no problem. Here, I am tired after three or four rounds."

Fury has spoken with British great Lennox Lewis about life at Big Bear.

"When not training I am thinking about training, when I'm not thinking about training I'm sleeping, and when I'm not sleeping I'm eating, when I'm not eating, I'm resting, watching TV," he said.

"I don't leave Big Bear. I went down a mountain to Ontario last week, just to check everything was going right. I was feeling very tired in the gym – I was speaking to Lennox Lewis on the phone and he told me he got out of there after a week.

"He said he hated it and it was too hard. I went to sea level, and I was very fit."

Ever the showman, Fury joked with reporters he had been "wrestling bears at 6am" but that "he can't land on me".

He also said he could not rule out retirement after the fight, but only because all options are open to him.

"I don't look past Deontay Wilder, I'm only interested in that. I just want to win that, I might retire after that, I don't know," he said.