Neil Patrick Harris is the latest addition to the ensemble cast for the upcoming fourth installment of the “Matrix” franchise.

He joins Keanu Reeves and Carrie-Anne Moss, who will be reprising their roles in the film, as well as Yahya Abdul-Mateen II, who was tapped as one of the leads last week.

Plot details are currently unknown. While it was rumored a young Morpheus could appear in the movie, sources close to the film would not confirm Harris’ specific role.

Warner Bros. announced in August that a fourth “Matrix” movie is officially in the works, with Reeves and Moss returning and Lana Wachowski on board to write and direct. Warner Bros. Pictures and Village Roadshow Pictures will produce and globally distribute the film.

Aleksandar Hemon and David Mitchell co-wrote the script with Wachowski, who will also produce with Grant Hill. The film is expected to begin production at the beginning of 2020.

Warner Bros. has been trying for the last couple of years to find a way back into “The Matrix” universe, but a hold-up over producing rights slowed the project down. The studio has recently seen the opportunity to ramp up development, with Reeves boasting a strong summer that included box office hits “John Wick: Chapter 3 – Parabellum” and “Toy Story 4,” in addition to a solid script from Wachowski.

The three previous films — “The Matrix,” “The Matrix Reloaded” and “The Matrix Revolutions” — have collectively earned more than $1.6 billion at the global box office. All three were written and directed by Lana and her sister, Lilly, and starred Reeves and Moss.

The role is a huge land for the “How I Met Your Mother” star in what would mark his first tentpole at a major studio. Harris was most recently seen in the Netflix series “A Series of Unfortunate Events.” On the film side his recent films have included Alexander Payne’s “Downsizing” and David Fincher’s “Gone Girl.”

He is repped by CAA and Untitled Entertainment.

Jada Pinkett Smith is in negotiations to reprise her role as Niobe in “The Matrix 4.” She played the role in the previous three films. Deadline first reported the Smith casting.