The four-time World Championship winner laid down his cue last year after beating Ali Carter in the final in Sheffield.
Carter himself exclusively revealed to the Yorkshire Post in November that he believed O’Sullivan would not be able to resist the lure of a Crucible return.
Although no official word came from the Essex potter, his appearance as a fan for the Masters in January intensified speculation, and at a press conference yesterday O’Sullivan confirmed he will end his self-imposed exile to chase a fifth crown.
O’Sullivan will cue off the tournament on the morning of April 20, and despite playing just a few matches on the Snooker Legend Tour, the 37-year-old believes he can be a contender.
“I just thought it was time to come back,” said O’Sullivan, who will be the top seed in Sheffield as defending champion, despite dropping to a provisional 24th in the world rankings.
“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.
“Three or four months ago I was sitting thinking that I would rather be losing 10-0 in Sheffield rather than going for lunch, dinner or 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. It was in the back of my mind that I would come back, but I needed to come back with a clear head.
“I don’t find snooker hard mentally or physically. It is your job and you get used to it. I needed to take time out for other things.”
World Snooker, the sport’s governing body, revealed O’Sullivan must formally enter for the 2013 World Championship by tomorrow’s deadline.
Chances of a fifth world championship for a player who has only played 10 days competitively in nine months seem remote. But if anyone can do it, it is surely O’Sullivan.
However, he expressed doubts, conceding: “I’m very match rusty. I haven’t played any matches.
“I have not been in any intense situations so it’s going to be a tough call to go in there with no match practice behind me.
“I might get smashed in Sheffield. I’m going in to the unknown. It’s a massive challenge.”
O’Sullivan sought the care of a psychologist to help him, but he admits he cannot be sure that his personal problems will not affect his play when he returns.