Comedy comes in many shapes and sizes but occasionally there are mavericks who manage to create something so absurd that it’s brilliant. Britain has a proud history in this field. The forerunner was undoubtedly the peek into Spike Milligan’s mind afforded by The Goon Show in the 1950s. Monty Python and The Flying Circus followed. Chapman, Cleese, Gilliam, Idle, Jones and Palin revolutionised comedy forever. Whilst there have been many big egos in comedy, there has certainly been no one with a head large enough to rival that of Frank Sidebottom; but little is known of his creator.

Steve Sullivan’s new documentary Being Frank: The Chris Sievey Story succeeds in changing that. Frank Sidebottom was a force of nature, in a time where a distinctly adult performer could also be enjoyed on Saturday morning children’s TV. That was the ultimate joy of Frank Sidebottom as a comedic creation. So baffling that no one really knew what was going on. The same can almost be said for Chris Sievey too. A man repeatedly thwarted in his desperate attempts to earn a living a musician, with a total self-belief and bursting with creativity. Both ahead of their time in different universes.

Funded by fans (which is testament to his popularity), Being Frank: The Chris Sievey Story is a brilliant documentary which charts the life of both Chris and Frank. At times, it’s hard to distinguish where one ends and the other begins. Indeed, as the film so deftly illustrates, Chris gradually became subsumed into the character. Using a wealth of great archive footage and interviews with friends, family and admirers (including Jon Ronson, Mike Joyce, John Cooper Clarke and Mark Radcliffe), Sullivan pieces together the life of a remarkably inventive, troubled and fascinating man, and the monster he created.

The World Premiere of Being Frank: The Chris Sievey Story takes place at SXSW on 13 March. The film also screens on 14 and 17 March.