The star becomes the latest addition to an ensemble that includes Joaquin Phoenix, Lady Gaga, Zazie Beetz, Brendan Gleeson, and Catherine Keener. Warner Bros. are yet to comment on Lawtey's casting in the film but insiders suggest he will have a major part in the flick.
Plot details for the new movie have been kept under wraps but Phoenix is reprising his role as Arthur Fleck/Joker and Gaga is playing the role of Harley Quinn - the Arkham Asylum psychiatrist who falls in love with her patient. The movie is said to be set in Arkham - where Fleck ends up at the end of the original film - and will feature musical elements.
As with the original "Joker" film, Phillips is directing from a script he has penned with Scott Silver. The movie is expected to begin production in November with a plan for a theatrical release in 2024.
Gleeson recently revealed that he signed up for the film in order to work with Phoenix again after the pair starred in the 2004 movie "The Village" together.
Asked how the "Joker" sequel appealed to him, he told Collider, "It wasn't the material, which is a great way to get me out of having to answer any questions about the criteria. It was the achievement of the first film. I worked with Joaquin before on 'The Village'... And so I knew him from then."
The 67-year-old star added, "And that performance, I'm still in awe of it. That performance as Joker, in that first movie. It was one of the most extraordinary achievements I've ever had. And for Todd to have - Worked the movie around to allow for that, I didn't have to be asked twice. I really didn't."