After weeks of speculation following the Irishman's departure from Old Trafford, Keane knocked back offers to sign for Bolton, West Brom and Real Madrid to sign for his apparent boyhood heroes, Celtic.
Today it emerged that Real Madrid had asked Keane to wait another week before they made a decision on signing him, which was too long to wait in Keane's mind.
Celtic immediatley quashed reports claiming majority shareholder Dermot Desmond was contributing personally towards Keane's wages, reported to be around £40,000 per week.
Keane will be registered as a Celtic player on January 1st, but cannot play against Hearts that day, as the SFA rules you cannot register for a club and play on the same day. Keane's first opportunity for a debut will be against Clyde in the Scottish Cup on January 8th.
Roy Keane will wear the number 16 jersey for Celtic.