The documentary marks the start of the 17th edition of the festival and its final outing in its current timeslot.

The 17th Sheffield Doc/Fest kicked off last night with the UK premiere of Joan Rivers: A Piece of Work, screened simultaneously in two venues.

Rivers took part in a press conference before the screening, together with the film’s directors Ricki Stern and Annie Sundberg. The 77 year old US comedian said she was “beyond happy” with the documentary, which is a no holds barred chronicle of a year in her life.

“We didn’t want it to be one of those stupid puff pieces,” said Rivers. “If you’re going to do something, then do it right.”

Stern told Screen that she and Sundberg had been questioned over their decision to make a film about the comedian, following their last film, The Devil Came on Horseback, about Dafur’s genocide. “When people heard they would say why are you making a doc about Joan Rivers?  And for me it was obvious, her life as a performer is a life that not many performers live any more. Joan’s story which she wanted to tell was as an ageing woman performer.”

Sundberg added: “I think one thing that is starting chafe is the idea that each documentary has to have a social mission.”

Despite taking $3m at the US box office, the film will be broadcast of Channel 4 next week rather than receiving a theatrical release. “It’s really hard to make money out of theatrical docs in the UK and the P&A costs would have eaten into our profits,” said Stern.

The screening of Joan Rivers kicked off Sheffield Doc/Fest’s final November edition before the festival moves to its new June slot in 2011.