Michael Gray (Finn Cole) and John Shelby (Joe Cole) are brothers in real life.
Early in the casting process, series showrunner Steven Knight met both Jason Statham and Cillian Murphy in Los Angeles to discuss the key role of Thomas Shelby. Initially, Knight had instantly opted for Statham due to his imposing presence, but later changed his mind and went for Murphy after he received a text from him - "Remember, I'm an actor" - that ultimately convinced him to reconsider.
Cillian Murphy had smoked over 3000 cigarettes over the course of filming just by the end of Series 2. His current count would amount to around 6000 cigarettes on set. However, he has informed reporters that he smokes herbal cigarettes (they don't contain tobacco or nicotine, and hence aren't addictive) and the creator, Steven Knight joked that the herbal ones are so weak that they would "probably count as one of his five-a-day".
David Bowie was a huge fan of the show and gave permission for music from his final album to be featured in Series 3. The show's creator Steven Knight revealed: "I got in touch with his people, who came back straight away and said he was a big, big fan." Bowie later sent a representative from his label to provide an early hearing of his final album Blackstar a week before its existence was made public. "And then on the following Tuesday we heard that he'd passed away. It seems that his people were keen to establish that we could use it before he died."
Tom Hardy (Alfie Solomons) and Charlotte Riley (May Carleton) are married in real life. Their first child was born in October 2015.