The film emerged as his family paid an emotional tribute to their father. His youngest daughter, Bonnie, said her father was "loved not only by my family, but by many, many others".
"We will never forget him and neither will the world," she wrote online. "R.I.P to the man, the myth, the legend - my wonderful, generous, foul-mouthed and hysterical father. My idol now and forever.
"We love you daddy."
It is not yet known how Mayall died, but there is speculation his death was linked to a near-fatal quad bike accident in 1998, in which he suffered two brain haemorrhages and was on life-support for five days.
Peter Richardson, a family friend who worked with Mayall on Comic Strip Presents, said his son had spoken to the comedian just half an hour before he died, when he appeared to be "happily chatting away".
"It was very quick and we still don't quite know what happened but it was a seizure of some sort," he said.
"He always wanted to be a rebel but in fact was a lovely family man who did the washing up and was just a very warm person and not as selfish and vain as he liked to make out really."
Mayall's wife, Barbara Robbin, who is understood to have found him dead at their home in Barnes, southwest London, said he could have suffered a fit but "we just don't know".
The death, which is not suspicious, has now been referred to a coroner.
Mayall had been taking a short, planned break in between filming when he died, after completing The Escape, which is based on a 2007 book about a bored mother seeking to escape the drudgery of everyday life.
Mayall was also due to begin work on the second series of Damo and Ivor, for broadcaster RTE, and Channel 4 comedy Man Down.
Friends and family have rallied to support Mayall's wife and three children.
One neighbour told the Telegraph he had seen Mayall only days before his death, looking "fine".
He added Mayall had taken up jogging around a year ago, but had not been seen running recently.
Comedian Jennifer Saunders, wife of Mayall's comedy partner Ade Edmondson, thanked well-wishers for their tributes, adding: "It is terrible to lose Rik so young."