Joaquin Phoenix Calls Mom His 'Inspiration' at Critics' Choice: 'You've Never Given Up on Me'

Joaquin Phoenix has another trophy in the bag — and he’s thanking his mother, Heart Phoenix.

The actor, 45, won the Critics’ Choice Award for best actor on Sunday night for his performance as Arthur Fleck in Joker.

“I need to thank my mom. Mom, you’ve always been my greatest inspiration, even when self-pity led me astray,” Phoenix said. “You’ve never given up on me and I deeply appreciate your support.”

Next, the actor thanked screenwriter Scott Silver, saying, “You used a superhero character to talk about childhood trauma, gun violence and mental health.”

This is Phoenix’s second major award of the year, having come off a Golden Globe win for best actor in a motion picture, drama for his portrayal of a mentally ill comedian who turns to violence and crime.

Phoenix told reporters backstage at the Globes that getting into character as Fleck “was a long process.”

“I think the way I worked on this was quite erratic,” Phoenix said. “I didn’t attack it linearly. I was most curious about the medication that he was taking and the effects and side effects of the medication. That led us to realize that we had to have this fluctuation of weight.”

“I dug into understanding medication and the side effects of what he was taking so that was the beginning,” he continued. “I read several books about political assassins that share a similar personality type.”

RELATED: Joaquin Phoenix’s Joker Gets Major Oscar Buzz After Winning Top Award at Venice Film Festival

With another win, Phoenix is likely to land an Oscar nomination when the nominees are revealed on Monday. In November, the film surpassed $1 billion at the worldwide box office, making it the first R-rated film to do so.

The movie, directed by Todd Phillips, earned critical acclaim at its debut at the Venice Film Festival in late August — it won the Golden Lion award at the festival — and was again applauded at the Toronto International Film Festival in September.

Joker is in theaters now.