Matt Damon dusted off his southern accent on Tuesday, briefly aping President Clinton's signature drawl at a Clinton Global Initiative event in New York.

"The president has been great, and when we talked to him, to President Clinton a few years ago, he said, 'just keep running those numbers up. Just run 'em up,'" said the Good Will Hunting star, who attended CGI to plug clean water initiatives.

President Obama, whose speech about civil activism followed Damon's water talk, laughed about being the runner-up attraction.

"Always wonderful to follow Matt Damon. I saw people trickling out after he was done," the former president quipped. "These are the hard core policy people who decided to stay for me."

But Clinton ended on a more somber note:

"No matter how dark the hour, we remember the words of Dr. King: the time is always right to do the right thing," he said. "Dr. King also said that the arc of the moral universe is long, but it bends toward justice. The reason we support civil society is because we have seen in this country of ours that it does, in fact, bend towards justice, but it does not do so on its own. It does so because there are hands of ordinary people doing extraordinary things every single day."

The Clinton Global Initiative, an annual conference organized by the Bill, Hillary and Chelsea Clinton Foundation, is in its 10th year.

ABC's Liz Kreutz contributed to this report.