But “Late Night” continued on, this time with O’Brien as the new host.

As a newcomer to the late night circuit, his first four months on the show sucked.

NBC also made it clear that he “probably wouldn’t be around for very long.”

David Letterman on the red carpet

That was until David Letterman asked to be a guest on the show.

“It’s easily one of the happiest nights of my professional life.”

O’Brien credits Letterman’s appearance as the night that his version of “Late Night” turned everything around.

David Letterman and Conan O’Brien interview

“And we survived.”

The comedian credits Letterman for saving him, for reasons he still doesn’t understand.

“I still believe that that simple act of kindness turned everything around and made all the difference.”