Dermot Mulroney actually plays the cello in real life. He is a classically trained cellist who began playing in Alexandria, Virginia's public school system when he was 7 years old. He plays with the scoring orchestras on many films for Academy Award winning composers such as James Newton Howard and Michael Giacchino
Nathalie Emmanuel is a British actress who portrays an American in the show. She tries to imitate an American accent for the entire show.
As per Mindy Kaling's Instagram, principal shooting began in London in November 2018
Rupert Vansittart appeared in both the 1994 film and the 2019 mini-series Four Weddings and a Funeral. He had the part of "George the Boor" in 1994, and portrayed Kash's boss at Goldman Sachs, also called "George". Whether or not it is the same character is not clear.
Several of the friends live in the London neighborhood of Notting Hill. Hugh Grant, who starred in the movie version of Four Weddings and a Funeral, also starred in the movie Notting Hill. An additional homage to Notting Hill is the "Ain't No Sunshine" montage, where Kash walks through the market over the course of a year, just like Hugh's character does.
Maya, Craig, Duffy, and Ainsley all share the same first line (the F word) in each of their introduction scenes.