The Hollywood actor, a longtime campaigner for peace in Sudan, and R&B superstar Alicia Keys are among the celebrities taking part in We Want Peace, a music video by Sudanese rapper and activist Emmanuel Jal, to raise awareness about the Global Initiative for the African country.
Rocker Peter Gabriel, Virgin mogul Richard Branson, ex-United Nations Secretary General Kofi Annan and former president Jimmy Carter have also lent their voices to the cause.
Jal, a former child soldier, tells MTV.com, "The issue has been there for a while, but we're trying to gather support to raise awareness... If people know, they will do something."
A preview of the video features Alicia Keys calling on the "whole wide world" to scream out for peace, amid rising tensions and fears of a north-south war in the nation.
The video's timing is critical as the Southern Sudanese prepare to vote for independence in January (11).