In early February 2021, Channel Four announced that their "On Demand" service, always available in the UK and Ireland, All4 shared that "It's a Sin" has been viewed over 6.5 million times, and has broken records including becoming their biggest ever instant box set, their biggest ever drama launch, becoming their most binged new series ever and their third biggest series ever. This was only in the first 5 weeks since Episode 1 premiered in the UK (and Ireland) on Channel Four and All4.
The character of Jill is based on actress Jill Nalder, a long-term friend of writer Russell T. Davies. She plays Jill's mother in the series, and had genuinely lived in a Hampstead flatshare christened the Pink Palace. A theatrical "La!" was a common callout amongst the friends.
On the night Channel Four premiered episode 1, they ran one of the Channel's original early 1980s revolving coloured blocks animations identities, before the continuity announcer gave a warning about the programme content, giving the episode the feel of the actual 1980s. The episode continued with the original colour version of the Channel Four logo.
There is a subtle tribute to the actor Ian Charleson, who starred as Eric Liddell in Les Chariots de feu (1981). Charleson died of AIDS on January 6, 1990 at the age of 40. A theatre poster from the 1982 West End cast of "Guys and Dolls" in which Charleson starred as Sky Masterson is seen hanging on the wall of a flat.
The series' creator Russell T. Davies made a point of casting all the gay roles in the show with real gay actors. He has made it clear on many occasions he doesn't believe straight actors should play gay characters.