Do you look back at the end of a season to see what you've learned about the show, or are you just constantly looking forward?

Well, both, always. I learned so much from this process of creating the show. And you know, you're constantly thinking about, “What haven't I seen that I'd like to see with these characters in the future?” Expanding on that premise, which could easily last a season, could take us to places that feel like, “What the hell?” How could this all happen in reality? From the beginning, we conceived our show as a slight touch of non-reality, a romantic look at New York City and its lonely residents. And it's true crime storytelling, so to me it feels like I'm always going: What do I want to see next from the characters? And do the characters hold the screen in a way that captivates and surprises me?

When they take Jan away at the end, she says to Charles: “We're at the end.” How far along do you think the show is planned? Do you know how the show will end?

(producers) Dan Fogelman, Jess Rosenthal, and I talked about story ideas and what they might look like. But I'm not that guy. I think I'm in such a special moment on this show because of how lucky everyone was to be a part of it and how lucky I am to be a part of it all. Until they tell me I can't do it, I'll keep going.

Save one of the best teases for next season for almost the final season: the introduction of Téa Leoni as a clearly formidable “lady” who wants to hire Charles and company to find her missing crime boss father.

I enjoyed every conversation I had with her. I've had a few text messages with her over the last week, which have been wonderful, with lots of thoughts and ideas surrounding her character and the future of season five.

Has the show grown in ways you couldn't have imagined when you first started?

I stood on the set of the seventh episode and that majestic brawl between Meryl Streep and Melissa McCarthy among this group of actors – Molly Shannon, Steve Martin, Martin Short, Selena Gomez, Zach Galifianakis, Eugene Levy, Eva Longoria– We all just stood there and watched them both, it was one of those moments where you feel like you're in an Al Hirschfeld drawing.