David Letterman shares poignant tribute to Robin Williams

Veteran US talk show host David Letterman paid tribute to the late Robin Williams on his talk show last night, fondly remembering a friend and colleague he had known for almost 40 years.

The Late Show with David Letterman returned to the air last night after a week's hiatus, and Letterman used the opportunity to reminisce about how he had first encountered Williams, 38 years ago at the comedy store.