Warning: Major spoilers for Joker ahead!
When Thomas Wayne (Brett Cullen) first appears in Joker, it seems as though he will only play a small part in the film, helping to make you feel like you’re really in Gotham City.
Wayne is running for mayor and is so far removed from Arthur Fleck’s (Joaquin Phoenix) world it doesn’t seem like the pair will have much of a connection other than the fact Arthur’s mother once worked for the Wayne family.
However, things take a significant turn when Arthur finds out he may be the illegitimate son of Thomas Wayne. Brett Cullen, who played Wayne in the film, was just as surprised to find out about the twist, however, notes it was very important that it was included in the film.
Cullen revealed to The Hollywood Reporter that he spoke to director Todd Philips about the connection and Philips explained that it was a way to explain Joker’s hatred for the Wayne family, but in a way that the audience would sympathise with him.
“I was very surprised when I read the twist. I went to Todd and asked, ‘Are we playing this the way I think we’re playing this’ Todd responded with, ‘What would be a compelling reason for the Joker to hate Batman so much?’
“The idea that the Joker is an illegitimate child that didn’t get anything from the Wayne family is a very compelling motivation for his character’s hatred. This movie makes you feel for Arthur, when you see him struggling with his mother. And she’s saying, ‘Go see Thomas Wayne, he’ll help us. He’s a good man.’ It’s gut-wrenching.”
We later find out that Arthur isn’t actually Wayne’s son and that his mother had been suffering from mental illness. There is then evidence that Arthur was actually adopted and had been abused for much of his childhood.
The audience is left to question the truth of Arthur’s parentage, but Cullen revealed he approached his performance as if the affair was real and added that he believes Wayne was responsible for having Arthur’s mother committed to Arkham Asylum.
“I asked Todd how Thomas Wayne would’ve know Arthur’s mother. The backstory was that Arthur’s mother had worked for Thomas in his home, and she was a beautiful woman who Thomas was attracted to and it led to a physical relationship… Later in life, she’s in and out of mental institutions. And in my mind, Thomas Wayne put her there.”