Industry observers were taken aback when actor Joaquin Phoenix, seemingly on top of his game after the Johnny Cash biopic Walk the Line, announced he was giving up acting and turning to music instead. An artist in turmoil, or was it all an elaborate hoax? Now we have this seemingly serious documentary, filmed by his brother-in-law and fellow performer Casey Affleck, to flirt with those questions and tease us by not giving us any answers. The Phoenix seen here – bearded, rotund and with obvious substance-abuse issues – is clearly not doing any future career in film or music (he’s not exactly a gift to hip hop) any good at all, but the fascination of this unique project is sensing the moments where the unfolding drama tips us the wink or famous cohorts like Sean Combs or Ben Stiller are too obviously playing along. With shades of Von Trier and large doses of Hollywood madness, this is as unclassifiable as it is queasily compelling. (Notes by Trevor Johnston).