LONDON.- In January 2019, Lucy Moss and Toby Marlow, the creators of the musical “Six,” were on a writer’s retreat in Connecticut, wondering how to follow up their celebrated first show.

That month, “Six” — in which Henry VIII’s wives tell their stories via pop songs — was starting a major West End run, and a Broadway transfer was on the horizon. The show had already been a hit at the Edinburgh Fringe Festival, and a growing number of American fans were streaming the show’s soundtrack. More and more, people wanted to know what the pair would do next.

During the Connecticut retreat, they struggled to come up with new ideas, Marlow recalled in a recent interview, and instead gossiped about their love lives. Then, they had a breakthrough: “Maybe this is what we should write about,” Marlow said.

On Wednesday, Marlow, 29, and Moss, 30, announced that their second musical, “Why Am I So Single?,” will open at the Garrick Theater in London on Aug. 27.

The show, which has a 12-person cast, follows two friends struggling to write a musical and asking each other why they’re chronically single. That idea may sound similar to the creators’ time in Connecticut, but Moss, laughing nervously, said it was “definitely not a complete autobiography.”

Marlow said that the musical, which includes songs inspired by Dua Lipa hits and numbers from “Singin’ in the Rain,” was “about friendship and love and loneliness and everything that goes with it.”

“Six” is still running on Broadway and the West End, and in 2022, it won the Tony Award for best original score. There are also multiple touring versions, including one on a cruise ship. Because of that success, anticipation for “Why Am I So Single?” has been building since a song the duo was working on appeared online a few years ago. Last fall, Marlow and Moss staged a brief run of an early version of the show in London.

During a recent 30-minute interview, the two friends discussed how “Six” changed them and the multiyear writing process behind “Why Am I So Single?” Here are edited extracts of that conversation.

Q: How are you feeling announcing your second show?

MOSS: Wildly oscillating between incredibly excited and extremely nervous and stressed. But that’s good. It’d be weird if I was chill.

Q: The new show sounds so different from “Six.” Did you set out to distance yourselves from it?

MOSS: After “Six,” people would approach us, like, “Why don’t you do this other historical show?” or “How about this other feminist revisionist idea?”

But the thing we were excited about with “Six” was its form, and our connection to it, rather than it being historical. “Six” was just an accident really — us trying to write a show that showcased our university friends who were women and nonbinary people. The six wives was just what was out of copyright and what we could use as a hook to get people to come and see it.

Q: You wrote “Six” while still at college, at Cambridge University. How did the pressure of such an early success affect you?

MARLOW: It was a lot. It instilled this idea that because we’d had this unexpected success very quickly, there’d be something else delivered just as quickly. Soon, we were failing to write anything, probably because we were being debilitated a bit by that pressure.

MOSS: In 2019, we spent about four months trying to write another show we’d been commissioned for, working in a freezing shed, 10 a.m. till 6 p.m., Monday to Saturday. It was a total disaster.

MARLOW: Looking back on that time, a lot of the stress was feeling, “What if we don’t manage to write something else?” The relief that I felt when we put a full stop on our first draft of “Why Am I So Single?” was so amazing. It was this moment of “Oh, my God, I don’t care if everyone hates it. We can still do it!”

Q: How did you cope with that pressure?

MOSS: What’s really nice is that we are in it together. I know lots of writers who face that pressure on their own. That can make them lose a bit of their sense of self. But I feel we’ve always had each other, that’s been our saving grace.

Q: Did your friendship change during this time?

MARLOW: We’ve done a lot of work on our relationship to carry on working together — learning to trust and to be honest and give people the benefit of the doubt. So many of those things I’ve learned, I’ve applied to all the relationships and friendships in my life, and I’m really grateful for that.

Q: Was the writing process for “Why Am I So Single?” different from “Six”?

MOSS: “Six” was us bashing out songs to this loose concept, whereas this has been many, many, many hours and days talking about structure and character, and plotting the show with sticky notes all over the walls. It felt very much more like constructing a musical in a traditional sense.

Q: What is your hope for this new show? Do you want it to become like “Six,” a juggernaut that is performed on cruise ships?

MARLOW: I definitely want to go on a cruise when it’s done! I don’t know. I hope people like it.

MOSS: I hope single people — and non-single people! — watch it and then leave the theater feeling reassured and uplifted by the love that they have in their lives.

This article originally appeared in The New York Times.