David Kaff has died aged 79

Mutual of Alameda's Wild Kingdom, his band, said in a Facebook post: "Our brother David Kaffinetti passed away peacefully in his sleep. We are devastated by this event. David always had a kind word and a quick wit that would slay you where you stand. Then he'd make you smile doing it! RIP dear brother (sic)"

Kaff's cause of death has not yet been revealed.

The musician - whose real name was David Kaffinetti - was a founding of the progressive rock band Rare Bird, which released five studio albums between 1969 and 1975.

Sympathy, the band's 1970 single, is estimated to have sold one million copies globally.

Kaff was cast as a Viv Savage in This Is Spinal Tap, the mockumentary comedy film co-written and directed by Rob Reiner, which was released in 1984 to critical acclaim.

Kaff starred in the movie alongside the likes of Christopher Guest, Michael McKean and Harry Shearer, and he even appeared in the band's Saturday Night Live performance in 1984.

The musician had a relatively small role in the film, but he still became well-known for some of his memorable lines, like "Have a good time ... all the time" and "Quite exciting, this computer magic!".

Kaff admitted in 1991 that he actually shared a lot of traits with his on-screen character.

He told BAM: "I played him very close to my heart, just a little bit dimmer. If people like that character, chances are they'll like me."

After cutting ties with Spinal Tap, Kaff went on to star in the bands Model Citizenz and Mutual of Alameda's Wild Kingdom.

And while a sequel to This Is Spinal Tap - entitled Spinal Tap II: The End Continues - is slated to be released later this year, Kaff is reported to have had no involvement with the project.