On Wednesday night, Conan O’Brien implored viewers to switch channels and tune into David Letterman’s last episode of last-night television, but not before taking the opportunity to speak about “something incredible that Dave did for me almost 22 years ago.” That something is Letterman’s appearance, back in 1993, on Late Night With Conan O’Brien, which had been severely panned by critics. 

Letterman’s unsolicited visit was a blessing for the struggling show: As O'Brien notes, the host was at that time the premier personality on television, and his generous support gave Conan and his staff the confidence that “maybe, just maybe, we can earn the right to be here.” They did that and more.