Some of Hollywood's biggest stars attended the 9th Annual Clinton Global Initiative this week, and they weren't just there to throw money at the world's problems.
PICS: Candid Celeb Sightings
President Bill Clinton explained to ET's Nancy O'Dell that one of the conditions of coming to the event is to make a commitment to change the world for the better.
"A lot of these people want to actually get their hands dirty," Clinton said of his celebrity supporters.
Clinton cited Brad Pitt's rebuilding effort in New Orleans' Lower Ninth Ward and Angelina Jolie's ambassadorship as prime examples of the lengths that some stars will go to help the less fortunate.
Since 2005, the Clinton Global Initiative has been bringing together corporate and social leaders to implement innovative solutions to the world's most pressing challenges.
"We've got commitments that have already helped more than 400 million people in 180 countries," Clinton said.
Watch the video for more.