Ronnie O'Sullivan has ended his sabbatical from snooker and announced he will defend his world title.

O'Sullivan said in November that he would not compete for the rest of the season, ruling out another crack at the World Championship this year, but he today went back on that decision.

The 37-year-old, appearing at a press conference in central London, said he will take part in the tournament at the Crucible, which begins on April 20.

And he insists he can be a contender, despite his lack of match practice.

O'Sullivan said: "I just thought it was time to come back. I have a different perspective now.

"I am used to being written off. I know how good I am and that I can do this."

O'Sullivan, widely regarded as the most talented player in the history of the sport, has played just once since winning his fourth world title last May - a drab loss to the unheralded Simon Bedford at a minor tournament in Gloucester.

With the entry deadline for this season's World Championship falling on Thursday, he has made his choice just in time and World Snooker have confirmed he will be in the line-up, beginning his campaign on the opening morning of the tournament.

There was speculation that O'Sullivan might call it a day for good, but the Chigwell-based cueman will instead start among the favourites as he targets a fifth Crucible crown.

"This is a massive challenge but I see this as the start of a bigger picture" - Ronnie O'Sullivan

The loss to Bedford was his only competitive outing since beating Ali Carter at Sheffield in May, and despite his November address saying he needed a break, he today admitted to being bored.

"Three or four months ago I was sitting thinking that I would rather be losing 10-0 in Sheffield to be back playing, rather than going for lunch, dinner and chilling out," he said.

"I got bored and had to get back to playing, winning or losing, and it shows how big a part of my life snooker is.

"I feel refreshed, I was never out of juice. I needed to take some time out, but not too much time, and I had it in the back of my mind that I would come back to playing snooker, but I needed to come back with a clear head."

O`Sullivan has been playing on the Snooker Legends tour with long-time friend Jimmy White, but that is as far as he has gone.

With that in mind, he knows how difficult it will be for him to get up to speed for his opening match, which will come on the first morning of the tournament.

"I`ve played three or four exhibitions but I`ve played 10 days in nine months," he added.

"I`ve potted lots of balls, but I`m match rusty. I`ve not played matches in tense situations and it`s going to be a tough course with no practice.

"You can never replicate match situations anywhere else. This is a massive challenge but I see this as the start of a bigger picture."