Sir Paul will feature alongside the likes of Robbie Williams, Melanie C, Holly Johnson and Gerry Marsden on the single which is due to be released on December 17.
The acts, who are going under the name The Justice Collective, will raise money to cover the legal costs of the families of the Liverpool supporters killed in the Hillsborough disaster in 1989.
Each of the performers gave their time for free to record the single which has been produced by Robbie Williams's former songwriting partner Guy Chambers.
The track, which is already favourite to be the Christmas number one, recently had its first play in Liverpool in front of families of victims of the disaster.
Bookmakers expect the song to beat the X Factor winner to the festive top spot, in a repeat of last year's chart battle which saw the Military Wives choir beat Little Mix.