The Descendants star and film producer Jeffrey Katzenberg hope to raise $350 million (£219 million) to benefit the Motion Picture & Television Fund (MPTF), which provides heath care and other services to struggling showbusiness professionals and retirees.
Clooney says, "I was raised to believe that, as a community, we should be judged by how we take care of people who can’t take care of themselves. This is our community. This is our commitment."
The campaign has already raised $200 million (£125 million), thanks to numerous contributions made by the likes of Tom Cruise and Steven Spielberg, however the group is hoping stars will continue to dig deep.
MPTF executive Bob Beitcher adds, "The fact is that today we can’t anticipate what kind of help and support they’ll need from MPTF. But we can be certain that there will continue to be needs that otherwise won’t be filled without the support of our charity."
The non-profit organisation was founded in 1921 by Charlie Chaplin, Douglas Fairbanks and Mary Pickford, among others.