Actor John Simm discovered that his late father Ronald Simm was not his biological father during an appearance on ITV's DNA Journey with co-star Philip Glenister. Simm's real father, Terence Naylor, who passed away in 1998, frequented the same working men's clubs where John and Ronald performed together, raising the possibility they had crossed paths. The emotional episode also led to Simm meeting his half-sister, Karen, for the first time. The show captured the raw emotions and surprising twists faced by both actors as they explored their genealogies. Simm expressed relief that Ronald was not alive to be upset by the news, which also deeply floored his mother, Brenda.