Channel 4’s new drama It’s A Sin has been praised across the board for its powerful storytelling, incredible cast, and bringing LGBTQ+ history to a mainstream audience.

The show follows a group of five friends who move to London in 1981 only to find themselves growing up in the shadow of the HIV/AIDS epidemic that took hold throughout the decade.

Show creator Russell T Davies has lived with the idea for It’s A Sin for decades and has now revealed the single moment in the drama that actually inspired its creation.

“There’s a key little moment where Gloria says to Jill, ‘I heard there’s a production of Seven Brides for Seven Brothers, and all seven brothers died’,” Russell T Davies explained in the latest episode of It’s A Sin – After Hours.

“That’s a tiny little line that flies past you. The entire drama came from that.

“I heard that story round about 1989 or 1991 – I can’t date it – and as a joke it’s kind of awful. It’s horribly funny and blackly comic – it’s profane at the same time. It just made me think, ‘Wow, imagine if there were seven brothers in a cast and they all got wiped out.’ That made me think, imagine if I had a flat full of people…”

Russell added: “It’s just one joke that looks like a throwaway moment. I didn’t tell David Carlyle [who plays Gregory/Gloria], the actors, or the director because I didn’t want to add too much weight. But that joke created the entire show.”

It’s A Sin stars Omari Douglas and Lydia West join host Kemah Bob for this week’s It’s A Sin – After Hours where they talk about the real-life Jill and the importance of allies.

They are also joined by one of our favourite allies, Little Mix’s Jade Thirlwall, who speaks about how it’s important that the HIV/AIDS story is being told through a British perspective.

It’s A Sin – After Hours launches weekly after the main show on Channel 4 and is available to watch on Channel 4’s official Instagram and on YouTube.

It’s A Sin airs at 9pm on Fridays on Channel 4, with all five episodes available to stream on All4 now.

Related: It’s A Sin: Lydia West and Jill Nalder discuss the power of allyship during AIDS crisis