Paul McCartney is one of more than a dozen celebrities who've joined the Justice Collective, a group aiming to raise money with a charitable cover of the Hollies and Neil Diamond hit 'He Ain't Heavy, He's My Brother.' The song -- to be released on iTunes Dec. 17 -- will support the families of the Liverpool 96 as they fight for justice concerning a 1989 soccer tragedy at Hillsborough Stadium in Sheffield, England. It's available for pre-order now. 

The tragedy at the FA Cup semi-final is among the worst sporting disasters in history. Original findings blamed the fans for deaths of 96 people, but subsequent investigation has revealed shoddy police work, inadequate exits and turnstiles and improper medical response led to most if not all of the fatalities.

In addition to McCartney (seen at about the 3:01 mark), Robbie Williams, Shane MacGowan, Gerry Marsden, and Mel C. appear. Paloma Faith, John Power and Eliza Doolittle are a few others who sing along with two former Liverpool football players (the 96 killed were fans of Liverpool).

A push to get the song to No. 1 in England is being promoted at the charitable single's Facebook page. Proceeds will go to the families' legal battles.