There have been many moving Robin Williams tributes recently, but this one definitely sets itself apart.
In his first show back from break, David Letterman took more than 10 minutes to honor Williams, his friend of 38 years. During the segment, Letterman recalls first meeting the actor when they were just getting into the business and introduced a video of Williams' appearances on "Late Show," which includes a clip of Letterman himself on "Mork & Mindy."
The "Late Show" host ends the moving segment by admitting, "I had no idea that the man was in pain, that the man was suffering."
Watch the video above and see the rest of Letterman's appearance on "Mork & Mindy" below.
"Late Show with David Letterman" airs weeknights at 11:35 p.m. ET on CBS.