Why is only one of the Wachowskis returning for The Matrix 4? After years of speculation and rumor, a fourth film in the Matrix series was officially confirmed earlier this month, surprising fans with the news that both Keanu Reeves and Carrie-Anne Moss would be returning, even though their respective characters died in The Matrix Revolutions. Furthering that sense of continuity, it was also announced that original director, Lana Wachowski, would be plugging back into the Matrix for the upcoming sequel.

Matrix fans were delighted, not only by the return of Reeves and Moss, but also knowing that one of the minds responsible for first crafting The Matrix and bringing the idea to life would remain involved in the franchise's future. The vision and ambition of the Wachowskis in the late 1990s was vital to the success of the original movie, and the duo were responsible for some iconic action sequences, as well as widely acclaimed cinematography and one of the most expansive and detailed fictional sci-fi worlds in recent memory. Curiously, however, only Lana Wachowski was announced for The Matrix 4, even though the sisters have primarily worked as a pair throughout their career.

Related: The Matrix 4: How Keanu Reeves Can Return (Despite Neo's Death)

This is because Lilly Wachowski began an extended break from the entertainment industry around 2016. Having previously worked together on the first season of Sense8, season 2 was instead written and directed by just Lana, along with Michael Straczynski. This marked the first occasion Lana Wachowski was without her sibling while working on a film or TV project. Speaking at the TV Critics Association tour earlier this year (via Decider), Lilly described herself as having "one foot out the door" with regards to science fiction.

Wachowskis on Matrix set

The director also explained that science fiction usually relies and thrives on subtext but, since her transition, she hasn't felt compelled to pursue stories heavy in subtext. As a result, Lilly's only recent on-screen project is the upcoming drama/comedy Work In Progress, a project she describes as a once in a lifetime opportunity.

Some fans will understandably be a little disappointed that the entire original team won't be getting back together for The Matrix 4, especially considering Lilly's contribution to the original Matrix trilogy. However, the director's passion for science fiction has obviously dimmed somewhat in recent years and it makes little sense to tackle a huge project like The Matrix 4 if there's no passion behind it. To do so would be detrimental to both the movie and the individual. Clearly, Lana Wachowski still has a strong interest in making mind-bending science fiction visual feasts, and it makes far more sense to have her go solo on this occasion.

Lilly Wachowski hasn't closed the door on a future full-time return to the movie business, however. It's also possible that The Matrix 4 could act as a springboard for a whole new trilogy, meaning a Wachowski reunion on The Matrix 5 can't be completely ruled out.

More: What If The Matrix Was Cast Today?

The Matrix 4 is currently without a release date. More news as it arrives.