The two movies show the power of true reality versus mock reality, though. All Gilliam lost was a movie and some pride, while brothers Tom and Barry Howe lose themselves in a tragic haze of intertwining identity and fraternal resentment.

But Gilliam’s misfortune packs more emotional wallop, his story immediate and funny and human. Pepe, Fulton and screenwriter Tony Grisoni, who had worked on Gilliam’s Quixote picture, inject great detail into the Howes’ story, yet the siblings feel distant and disconnected, a couple of ciphers you never really get to know.

Adapted from Brian Aldiss’ novel, “Brothers of the Head” flits from present-day “recollections” by intimates of the Howe brothers to “archival footage” shot by a documentary filmmaker in the ‘70s.

Tom and Barry are joined at the lower chest and raised by their father and older sister in a coastal cottage in England. At 18, the boys are sold by their father to music promoter Zak Bedderwick, who puts them into training as a novelty act, petulant Barry singing, more easygoing Tom playing guitar.

Twins Harry and Luke Treadaway make a daring and difficult screen debut as Tom and Barry, copping a natural, familiar poise as brothers who must practically sit in each other’s laps and walk with arms slung around the other’s torso.

The filmmakers meticulously re-create the look and tone of the ‘70s hairstyles, clothes and music, the scenes of Tom and Barry playing sweaty pubs looking like vintage material from an early Sex Pistols show.

Interviewees include director Ken Russell as himself, who’s such a good sport he lets Pepe and Fulton incorporate footage of an unfinished dramatic film Russell is supposed to have shot about the Howe brothers.

A documentary, even a fake one, is only as good as its subject, and despite their peculiar condition and the strange little circus act of minions surrounding them, the siblings are rather bland early on. Other than their physical connection, they could be any other broody teens fronting a band.

“Brothers of the Head” belatedly picks up dramatic momentum in its final act, as the story slips into musings about merged and secret identities, a seemingly tossed-off lyric in one of the siblings’ songs, (“are you you or are you me?”) gaining importance as the story unfolds.
The songs and the Howes’ performances seem deliberately bad at first. Their music grows in confidence and skill as the documentary progresses, though it remains at the level of any number of forgettable angry punk bands of the ‘70s.

The Howes have their own Yoko Ono, a journalist (Tania Emery) whose romance with Tom strains the brothers’ relationship and leads to some interesting scenes of intimacy.

The biggest strength of the film is Pepe and Fulton’s eye for stark, neo-gothic imagery. They have a great sense of place, their ability to infuse desolate landscapes with surreal, melancholy grandeur a great asset should they move on to more conventionally structured dramas.

“Brothers of the Head,” an IFC Films release, is rated R for language, drug use and sexuality. Running time: 93 minutes. Two and a half stars out of four.