Louie asks Posey's Liz out and ends up pulling a crazy all-nighter.
"I wanted to write something about a long date that leaves you in the dust. That was in my head, and then I met Parker when we did a reading of a play for charity, and she was really good and had this really audacious voice. We hung out afterwards, and she made me laugh and was kind of nutty and fun, so I wrote that for her."
Lynch's character coaches Louie through the Letterman-replacement arc.
"I wrote that part for Ben Gazzara, but he died while we were writing it. Then we thought about Jerry Lewis, and he passed. Then I sent it to Martin Scorsese, who said no. I thought David Lynch would be crazy and perfect."
When Louie hurts his back, he consults with Grodin's physician.
"I wrote this doctor character, and we were kicking around names. I've always loved Charles Grodin, but I had heard he had kind of retired. But he really liked the material. Ellen Burstyn is doing a part on the show, and she talked to him about it they did Same Time, Next Year on Broaway for years. He pops up in four episodes this season."
As himself, Broderick directs Louie in a movie.
"We worked together on a movie called Diminished Capacity, and we became pals. So I was looking for something to do with him. I did a movie called Welcome Home, Roscoe Jenkins, and it was my first real movie role. I stunk really bad. I just couldn't get my head around it. I couldn't do it well, and I had no confidence and felt very hated by everybody on the set. It was terrible. So I put that story together for us to do."
As herself, Rivers plays the object of Louie's affection.
"I had never met her. I saw A Piece of Work, and she was describing how she dealt with the tougher parts of her life, and I felt if she were in front of me I would want to kiss her. I thought, 'That would be great if I could play that moment out!' And now we're friends. She came over to my house for Thanksgiving this year."