RONNIE O'SULLIVAN has revealed he rejected a lucrative offer to appear in the "I'm a Celebrity" jungle in order to focus on his quest to claim a seventh UK Championship.

While the best contest in York today saw Stephen Maguire come from 4-0 down to beat world champion Mark Williams 6-5, O'Sullivan celebrated his 43rd birthday by cruising into the quarter-finals with a 6-1 win over Jack Lisowski.

But he could have been thousands of miles away if he had taken up the offer from ITV to become the third snooker player to appear on the reality show, after Jimmy White and Steve Davis.

O'Sullivan said: "I was invited this year but I decided to put it on the backburner. I'm sure in time I'll give it a go.

"Maybe they can move this tournament. I'll come flying in like Tarzan from Australia to York with my thong on."

O'Sullivan would have been one of the top-earning stars on this year's series but he prioritised chasing the £170,000 on offer to this year's UK winner at the Barbican.

O'Sullivan added: "It was never about the money or I would have gone into the Jungle. I would really like to do it but (not) when you think you can still win tournaments. It was about snooker first."

Hundred breaks in the fifth and sixth frames helped O'Sullivan punish Lisowski for a series of errors after the 27-year-old had won the opener.

After frequently admitting to falling out with the sport in the past, O'Sullivan has stressed his commitment to continued improvement, including working on new methods to maintain his place at the top of the game.

"I've played better but my consistency is better and I'm going through a transitional period at the moment," added O'Sullivan. "I've got to wait until I'm 100 per cent confident in what I'm doing.

"When I went to Sheffield (for the World Championship) last year I knew I wasn't going to do anything. I thought, 'Now's the time to reinvent myself'. I'm 43 today and I need to find a game that's capable of competing with these guys."

O'Sullivan is scheduled to return for his quarter-final match on Friday, and in the meantime insisted he would continue to keep up to date with events Down Under.

"I'll go for a nice meal tonight and watch a bit of the Jungle," he added: "Harry (Redknapp) and John (Barrowman) are nice, but I really like Anne (Hegerty) - she really seems to have gained some confidence."

Maguire, meanwhile, scored three consecutive centuries (122, 120, 109) then a 97 as he staged a remarkable comeback against Williams.

The Scot came from 4-0 down to lead 5-4 and, while he missed a simple yellow to effectively wrap up victory in the 10th frame, he recovered his poise to win the decider largely due to an outrageous double on the last red.

"That's the best comeback I've ever made," said Maguire. "At the interval I told my dad to get the car ready and we could be back in Glasgow by 7.30pm. I just decided to pull the cue back and hope for the best."