US rapper Snoop Dogg and 3D of Massive Attack have collaborated on a new song entitled 'Calling Mumia'.

The track paints a picture of the life of political activist Mumia Abu Jamal, who is on death row in America.

Jamal was jailed for allegedly murdering a Philadelphia policeman.

'Calling Mumia' features on the sound track to the film In Prison My Whole Life and can be heard on Massive Attack's website.

(by Jason Gregory)