Joaquin Phoenix's 'terrible' teeth transformation for Joker in before-and-after photos

Joaquin Phoenix has, once again, undergone quite the dramatic physical transformation for Joker: Folie à Deux , which will finally be released in theaters on October 5.

The 49-year-old actor won an Oscar for his first turn as Arthur Fleck in 2019's Joker , which was also a box office smash, and is hoping to repeat the same success, this time with Lady Gaga by his side.

Alongside his drastic transformation with his weight, however, a big change to the actor's appearance comes through his alteration to his teeth — and he has one of Hollywood's best to thank for it.

Take a look at Joaquin's change to his teeth for Joker and Joker: Folie à Deux, and learn more about the other ways in which he pushed his body to the limits…

What has Joaquin had done to his teeth?

© BFA / Alamy Stock Photo

In Joker and its upcoming sequel, the character of Arthur sports a set of teeth that are meant to evoke a feeling of disgust and decay, to denote that he is a down-on-his luck comedian barely scraping by.

His teeth show through his uncontrollable bursts of laughter and each time he pulls his smile wide open using his fingers while sporting clown make-up.

They are yellow and crooked, with the gums showing signs of decay as well, and as it turns out, his set was actually the work of a professional.

© TCD/Prod.DB / Alamy Stock Photo

Who transformed his teeth for Joker and Joker: Folie à Deux?

Cosmetic dentist to the stars Dr. Jon Marashi was actually the one responsible for helping Joaquin with his teeth. He has worked with the actor for a long time to help perfect his smile, and helped him imperfect them as well.

MORE: Nicole Kidman's teeth transformation in before-and-after photos — what has she had done?

© Getty Images

His other A-list clients include Ben Affleck , Halsey, Lindsay Lohan , Justin Timberlake , Pink , Vin Diesel, Tom Hanks , and many more, and he not only helped dirty the teeth up, but also promptly fixed them for the actor for the press tour for both movies.

He told Dentistry Today in an interview in 2019: "Joaquin Phoenix had me do his smile for his movie Joker . That was a blast, and his teeth looked pretty gnarly for the role."

This August, he shared a selfie with the actor, who visited him with a signed poster of the 2019 film, on which he had written: "Doc Marashi, the only dentist that gets paid to make people's teeth look terrible. What would they say at dental school?"

MORE: Joaquin Phoenix reveals that he and Rooney Mara have secretly married

While doing promo for the sequel, Joaquin's teeth are noticeably a lot straighter than his character's and much more even, while of course being significantly cleaner, the work of Dr. Marashi as well.

© Getty Images

What else did Joaquin do to transform for Joker?

Back in 2019, the actor made headlines with his controversial diet for the movie to lose weight, consisting of only lettuce and steamed vegetables. The result was Arthur's incredibly skinny frame.

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He admitted during the promotional cycle for the sequel that a lot of the discourse the first time surrounded his major weight loss, and was insistent on focusing on it less this time. However, he noted that both he and Gaga did lose weight for the role.

© Collection Christophel / Alamy Stock Photo

"I'm not going to talk through specifics of the diet, because I just think nobody wants to hear that," he said at the Venice Film Festival last month. "But this time, it felt a bit more complicated just because there was so much dance rehearsal that we were doing, which I didn't have last time."