The moment I’ve told anyone this week that I watched I’m Still Here — Casey Affleck’s alleged documentary on Joaquin Phoenix’s retirement from acting to pursue a career as a rapper — the first question is always the same: is it for real, or is it a massive Andy Kaufman-esque put-on?

The film never answers that question definitively — that would be contrary to the spirit of what Affleck and Phoenix have spent the past two years putting together, as well as to the full-on commitment Kaufman gave to his own stunts. In fact, I wouldn’t be surprised if Phoenix never completely comes clean on how much of this is fact, and how much is fiction. But it’s pretty clear that for the most part, this is essentially a large-scale performance art piece.

For one thing, Affleck has already admitted what’s fairly obvious in the film, that some portions are scripted. Affleck’s own father even appears, not as himself, but playing Phoenix’s father in the film’s closing moments. Also, camera setups are staged to allow for traditional two-shot conversations that rarely occur in actual documentaries. And outside the film itself, though Phoenix has been keeping a generally low profile, he has appeared, clean-shaven and lucid, at charity events and promotions, and has quietly been in talks to return to acting. The name of the production company Affleck and Phoenix set up is even a tell: “They Are Going to Kill Us Productions.”