David Spade was one of Chris Farley's closest friends during his short life. During an appearance Monday night on "Conan," Spade shared the story about how "Fat Guy in a Little Coat," from their movie "Tommy Boy," came to be.

"It's nice to talk to you about that because you saw it every day," Spade told host Conan O'Brien, who was a writer at "Saturday Night Live" at the same time Spade and Farley were performers on the iconic show. "Chris loved you, of course. That was a real heyday of great performers and writers. The writers were so good."

Spade then talked about how he shared an office with Farley at "SNL," which was attached to the office of Chris Rock and Adam Sandler. Spade told O'Brien that some of their best material came from when Farley was simply bored during writing sessions.

"I was trying to scribble away and write some crummy sketches, and he'd go, 'David, turn around,'" said Spade. "And I go, 'If this is Fat Guy in a Little Coat, it's not funny anymore. I don't like it.' And then he goes, 'No, it's not, I'm working on new stuff.'"

Spade explained that every time he would always turn around, and it was always Farley in Spade's tiny jacket.

"That's why we put it in the movie because we didn't really have much to do in there," joked Spade. "It was stuff in 'Tommy Boy' that was funny to us that we just hoped was funny to people, and it worked out."