Scottish FA Cup Celtic v Rangers, Sunday 12.15: It will not have been the news Rangers wanted to hear on the eve of the Old Firm Scottish Cup tie but John Hartson has signed a new contract and could stay with Celtic to the end of his career.

The Welsh striker ended weeks of speculation by agreeing a two-year deal with the option of a further 12 months which would take him to nearly 34.

In the short-term it has provided Celtic with a huge boost ahead of tomorrow's third-round match and in the long-term it has secured the services, and goals, of the striker through his best years.

"I'm very happy and very relieved because it has been dragging on for a while," said Hartson. "But I can honestly say I have never used any interest from other clubs to get this resolved with Celtic because although I knew my agent had had some telephone calls regarding my position of being out of contract in the summer I didn't know of any concrete offers. Anyway, I wanted to stay here."

Celtic's manager Martin O'Neill insisted: "Getting John to sign on again is like getting a new player. He has been in devastating form now he's fully fit again after two back operations and a spell around the time when Wales played England when he realised he had to get it together.

"John is a natural goal-scorer and it's great news for us all that he has signed this deal." Hartson's comeback from injury has been impressive given that those back problems were career-threatening and now he is promising more goals to add to his tally for Celtic.

"This is where I want to spend the rest of my career. I've scored 78 goals and I'm really proud of that because I've only started about 100 games and now I want to end this season with 30-odd, win silverware and do it again next year," he added.

"I would like to go on and get 150 or 160 goals for this club and really feel I've left my mark on it."

No one could ever say Hartson has had it easy getting this far and he reminded people of that when he went on: "I've had to fight for a place with people such as Ian Wright and Dennis Bergkamp at Arsenal and Ian Rush and Mark Hughes with Wales. Then there's been a bit of luck involved with my back as well because that's been in the lap of the gods and they've been kind to me.

"I have been very fortunate because it was really bad for me at one stage. My contract was running out, I was 28-years-old and flying in terms of the goals I'd been scoring before it happened; then you go under the knife and you're not sure what's going to happen."

A first operation was unsuccessful but a second cured the problem and now Hartson is well and truly back in business.

There was further good news for Celtic fans as O'Neill said he is progressing with talks to keep Bobo Balde and Neil Lennon at Parkhead as well, although the influential midfielder will miss this tie through suspension.

Goodwill to all men was conspicuous by its absence the last time the teams met in November when Rangers won 2-0 and the Parkhead pair Alan Thompson and Chris Sutton were sent off, Celtic's Henri Camara and Rangers' Nacho Novo were later banned for incidents that occurred during it and the Ibrox player Peter Lovenkrands was substituted after a half-time fracas.

On top of all that Lennon was accused of spitting on a Rangers scarf thrown at him by a fan and even O'Neill came in for some flak for his defiant after-match march over to salute the visiting supporters.

The Rangers manager Alex McLeish is confident there will be no repeat of that controversy. He said: "We are always under special rules in terms of players misbehaving and it can become a police matter. I have felt that discipline has been reasonably good in these games.

"So this one will be along the same lines in that respect. The players have to be mature enough to adhere to those rules. I don't expect there to be any hangover from the last game. I don't believe that is the way it will unfold."

McLeish could field two debutants in the shape of new signings Thomas Buffel from Feyenoord and Bojan Djordjic from Manchester United.