The 23-year-old Australia international admitted he was bitterly disappointed to miss out on a January move to Rangers, who offered £400,000 on transfer deadline day.

But his Old Firm ambitions are now set to be fulfilled at Parkhead after being persuaded by Socceroo team-mate Mark Viduka, a former Celtic frontman, to join the Hoops.

McDonald's agent Lou Sticca revealed: "It's all done and dusted and it's a good deal for everyone concerned, a win-win situation."

Sticca added: "Mark Viduka has been in the international camp with Scott for the Socceroos.

"When he told him it could be Celtic or Rangers there was only one team Mark was pushing for.

"Scott didn't need to be pushed to Celtic but Mark was a convincing advocate of what he could achieve if he chose Parkhead."

McDonald has hit 12 goals in 34 appearances for Motherwell this season, including one against Celtic in October.

He will be best known to Celtic fans, however, for the late double he struck against them for Motherwell on the final day of the 2004/05 season which handed the Bank of Scotland Premier League title to Rangers.

Last night Motherwell boss Maurice Malpas admitted: "It is well known that Scott wants to move on from Fir Park.

"The club has succeeded in securing a healthy transfer fee for him and ensuring that he will remain with us to the end of the season.

"No club would wish to lose a player of Scott's quality but we wish him well in the future."

McDonald could face his future employers in Bank of Scotland Premier League action on April 7, when Motherwell travel to Parkhead.

The former Southampton trainee revealed: "I have thoroughly enjoyed playing for Motherwell and I will leave with a lot of good memories.

"I hope the fans appreciate that I want to move on and develop my career and I would like to thank them for the support they have given me.

McDonald should seal his transfer before the end of the week, with the deal subject to him passing a medical.