Joker is knocking on the door of a box office milestone. The movie is expected to hit $1 billion when the box office numbers for Friday come in, according to Variety.

That is a huge and unexpected number for the movie, which was produced on a very modest $62.5 million budget. With a return that big, Joker will become one of the most profitable films in the history of cinema. It'll also become just the fourth DC movie ever to make $1 billion, joining Aquaman ($1.148 billion), The Dark Knight Rises ($1.081 billion), and The Dark Knight ($1.004 billion).

Joker will also become the first R-rated movie to reach $1 billion (not adjusted for inflation) and the 44th biggest movie in history in terms of box office results.

Because Joker was not expected to be such a commercial success, Warner Bros. sought outside investors to mitigate their risk if the film didn't land. Warner Bros. also reportedly gave director Todd Phillips and star Joaquin Phoenix lucrative back-end deals so they are reaping the benefits of Joker's oversized success at the box office.

DC has numerous new comic book movies in the works, including Birds of Prey (February 2020), Wonder Woman 1984 (June 2020), The Batman (June 2021), The Suicide Squad (August 2021), Black Adam (December 2021), and Aquaman 2 (December 2022).