The characters Billy the Kid and Maxwell Randall, aka the Green Baize Vampire, are inspired by real-life snooker players Jimmy White and Ray Reardon, aka Dracula, respectively.
The movie is a musical fable built around the real life rivalry between British snooker players Ray Reardon and Jimmy White, whom the Green Baize Vampire and Billy the Kid are loosely based on.
Pro snooker player Ray Reardon, inspiration for "the Green Baize Vampire", was nicknamed "Dracula" because his greased-back black hair and widow's peak made him look like Bela Lugosi. Whether he was actually a vampire has never been proven.