Ciarán Hinds and Kenneth Branagh grew up just a mile away from each other with both leaving Belfast to eventually attend the Royal Academy of Dramatic Art (RADA) although they were seven years apart in age and never met.
To capture moments of spontaneity, Kenneth Branagh would often secretly roll camera on scenes that Jude Hill (Buddy) thought were just rehearsals. Jude eventually began to suspect what was happening, so the crew taped over the red lights on the camera that signalled it was shooting. Many scenes in the finished film were these "rehearsals."
Kenneth Branagh wrote the screenplay at the encouragement of his friend, actor John Sessions. This would be Sessions' final film role, having passed away in November of 2020.
Various members of the production were actually born in Belfast, including writer-director Kenneth Branagh, Jamie Dornan (Pa), Ciarán Hinds (Pop) and Josie Walker (Auntie Violet).