Michael Bisping is Britain's most successful UFC athlete

Michael Bisping has exclusively told Sky Sports that he must win his upcoming UFC world championship fight quickly because he lacks the fitness to last the distance.

The Lancashire veteran has been drafted into the UFC 199 main event against middleweight champion Luke Rockhold at less than three weeks' notice due to an injury to Chris Weidman.

Yet Bisping, who has patiently waited a decade and could become Britain's first UFC champion, admits the chaotic realities of fighting Rockhold on short notice do not favour him because he's spent the past month on a movie set.

I need to put him away because five rounds favour him, let's be realistic about that. Michael Bisping

"It's not perfect circumstances but this is my lifestyle," he told Sky Sports in an exclusive interview. "It's short-notice, so bittersweet, but I've worked a lifetime for this.

"I need to put him away because five rounds favour him, let's be realistic about that. He'll be in better shape than me because he's been preparing for 10 weeks for a world title fight and I've been filming a movie.

Michael Bisping (left) aims a left hook at Luke Rockhold in 2014

"He'll look to drag this into a five-round war where he's got the advantage, that's a fact. I've got to take him out early so I'll go back to my younger days - live by the sword, die by the sword.

"I've got two-and-a-half weeks - my weight isn't too bad so I'll have to go on an extreme diet, but I wouldn't have it any other way. Two-and-a-half weeks of intense, crazy work.

"I actually texted [UFC president] Dana White on Tuesday saying, 'If someone is hurt, I'll take it'. I pitched my case. The first time I heard was the UFC announcement."

Michael Bisping (left) evades a punch from Luke Rockhold

Bisping has already met Rockhold and came off worse, dropping to a submission defeat in 2014 amid heated personal animosity.

The rivalry was sparked by Bisping's insistence that he had triumphed in a behind-closed-doors sparring session and that fateful tale still instills belief.

"I've fought this guy before in the gym then we fought for real, it's 1-1," the 37-year-old said.

Michael Bisping appeals to the referee after being cut above the eye by Luke Rockhold

"He never hurt me with anything. He head-butted me in the first round which opened a nasty cut. Up until that point it was going very smoothly. Congratulations to him for getting the job done but there were mitigating circumstances.

"Nobody was in there except for me and him - I know how he felt, and the strength of his kicks and punches. Those things make me comfortable in taking this next fight."

Bisping's most recent outing was a career-best win against former middleweight champion Anderson Silva at London's O2 Arena, with Rockhold watching from ringside.

Rockhold can be as smug as he likes but when I dropped him in sparring, he certainly felt it. Michael Bisping

Prior to that fight Rockhold told Sky Sports that "if we fought again I wouldn't need to keep my hands up" which drew laughter from Bisping.

The Brit replied: "I'm pretty sure Anderson said the same thing but he got dropped twice and out-boxed consistently. Rockhold can be as smug as he likes but when I dropped him in sparring, he certainly felt it. We'll see how smug he is after the fight.

"This isn't a case of cashing in and trying to earn a few quid before calling it quits. I just beat the greatest of all time, Silva, and I'm the only person to legitimately beat him.

"This is my destiny, I love the way it's come together."