Joker Origin Movie: 9 Key Influences You'll See In Joaquin Phoenix's Performance
3. John Wayne Gacy
It's quite a left-field source, but the very first sighting of Phoenix in full Joker makeup did immediately give off some John Wayne Gacy vibes.
A serial killer and rapist, Gacy was also a businessman who started doing voluntary work as a clown - he invented two characters, called Pogo and Patches - where he'd perform at local parties and functions. Gacy's involvement came after learning of a group doing so, known as... the Jolly Jokers, and he even became known as the Killer Clown after his crimes were revealed.
Gacy is also known to have said "You know… clowns can get away with murder," which, really, is actually something you can imagine the Joker saying. Phoenix's take presumably won't be a rapist, but the makeup, and the idea of a man who performs and hides his dark secret, does fit.