Hollywood stars proved once again that they could be there when needed.

Not On Our Watch, a humanitarian organization founded by actors George Clooney, Don Cheadle, Matt Damon, Brad Pitt, producer Jerry Weintraub and civil rights lawyer David Pressman donated $500,000 to the United Nations World Food Program in Darfur, following warnings that cash shortages could ground its humanitarian flights.

“Without immediate additional funding, humanitarian aid in the region will be crippled. We are proud to help ensure the survival of this lifesaving program and strongly encourage others to do the same. We are proud to help ensure the survival of this lifesaving program and strongly encourage others to do the same. Protection of these victims should not fall solely in the hands of charitable organizations. Governments have a responsibility to help those who cannot defend themselves,” Clooney was quoted as saying in a statement Thursday by the Associated Press.

"This contribution will make a difference to the millions of vulnerable women and children trapped there, and we hope it will inspire other donations," WFP's Executive Director Josette Sheeran said.

This is the first donation received by the WFP in 2008. The non-profit group said it needs $77 million in 2008 to sustain its operations. . The WFP expects to support some 180,000-aid workers from 180 agencies in Sudan, and about 70 percent of that is in Darfur.

Earlier this month, Drew Barrymore also donated $1 million to the WFP in an effort to stop world hunger.

More than 200,000 people have been killed and another 2.5 million displaced as a result of an ongoing civil conflict between Sudanese government-backed Arab militias and ethnic rebel tribes begun in 2003.