Boyhood director Richard Linklater is making an adaptation of the classic Stephen Sondheim musical Merrily We Roll Along, which is set to star Ben Platt, Blake Jenner, and Beanie Feldstein. But in classic Linklater fashion, he’ll be filming the entire musical in real time over the course of the next 20 years, via The Hollywood Reporter.

Merrily We Roll Along is a musical that depicts the lives of three friends: Franklin Shepard, a Broadway composer; Charley Kringas, a lyricist who partners with Frank; and Mary Flynn, a writer and critic. The show tracks the trio’s lives and friendships over 20 years in reverse chronological order. It starts with three old, bitter, and estranged characters, then jumps back scene by scene to how they got to that point until it gets the start of their friendship. For the movie, Platt is set to play Kringas, Jenner will play Shepard, and Feldstein will play Mary Flynn.

The movie adaptation from Linklater will follow that same story, but it will be filmed in reverse — that is to say, in regular chronological order. Playbill reports that the first portion of the movie (i.e., the final scenes) has already been filmed, with subsequent chunks set to be filmed over the next two decades.

Linklater is no stranger to long productions, of course. Boyhood, his acclaimed 2014 film, was shot over the course of 12 years, chronicling the actual aging of the actors in real-time. Merrily We Roll Along looks to be an even more ambitious production (to say nothing of the fact that it’ll also be a full musical).

The original stage production of Merrily We Roll Along debuted in 1981 and ran for just 16 performances. But in subsequent years, it has seen various revivals and productions around the world, including an off-Broadway production by the Roundabout Theatre Company in New York City earlier this year.

If all goes well, Merrily We Roll Along should hit theaters sometime around 2040, assuming the Earth still exists then.