Watch David Letterman's Heartfelt Tribute To Robin Williams

"The Late Show" host David Letterman on Tuesday paid tribute to actor and comedian Robin Williams, who he knew for 38 years.

Letterman recalled the first time he saw Williams perform at The Comedy Store, and recounted how Williams out-shined the other comedians.

"We’re like morning dew; he comes in like a hurricane," he said.

At the end of his tribute, Letterman played a few clips from the 50 times Williams appeared on "The Late Show."