Musician and comedian Neil Innes has died at age 75, CNN reports. Innes, a member of the Bonzo Dog Doo-Dah Band and the Rutles known for his collaborations with the Monty Python collective, “passed away unexpectedly” according to his agent, Nigel Morton. A statement on Innes’ website indicated he “died of natural causes” on Sunday, “quickly without warning and, I think, without pain.”

Born in Danbury, Essex, England in 1944 and raised in Germany, Innes first rose to fame in the late 1960s as a member of the Bonzo Dog Doo-Dah Band (later shortened to the Bonzo Dog Band), a group he formed with classmates at Goldsmiths College. Their sole hit, 1968’s “I’m The Urban Spaceman,” was produced by Paul McCartney under his alias Apollo C. Vermouth and climbed to #5 in the UK. Bonzo Dog’s song “Death Cab For Cutie,” which appeared in the Beatles’ 1967 Magical Mystery Tour movie, is where Ben Gibbard and company got their band name. In the early 1970s, Innes and Bonzo Dog bandmate Vivian Stanshall formed the band GRIMMS with members of the Liverpool Scene and the Scaffold, eventually releasing two albums together.

Around the same time Innes began working with the Monty Python collective. He had a hand in 1972’s Monty Python’s Previous Record and 1973’s The Monty Python Matching Tie And Handkerchief and played a significant role in the final season of Monty Python’s TV show in 1974, during an interim when John Cleese had exited the group. He thus became one of only two non-Pythons to be credited as writers for the show, the other being The Hitchhiker’s Guide To The Galaxy author Douglas Adams. Innes contributed songs to 1975’s Monty Python And The Holy Grail, including “Knights Of The Round Table” and “Brave Sir Robin,” and played various roles in the film. He appeared in Monty Python’s Life Of Brian as well. His work with the collective was explored in the 2008 documentary The Seventh Python.

After the end of the Monty Python TV series, Innes and Python’s Eric Idle created the series Rutland Weekend Television, which spawned their Beatles parody group the Rutles, aka the “prefab four.” Innes portrayed the John Lennon caricature Ron Nasty on the show and eventually in the film All You Need Is Cash. Some of the satirical songs so closely resembled the Beatles’ originals that the owners of the Beatles catalog took him to court over it.

In 1979, Innes started the BBC series The Innes Book Of Records, which ran for three seasons. He moved on into children’s entertainment in the 1980s, appearing in series including Puddle Lane and The Raggy Dolls, wrote theme music for those and others, and contributed to still other shows including Tiswas. Later on, he participated in various Monty Python, Rutles and Bonzo reunions, and more recently formed the Idiot Bastard Band. He released his final album, Nearly Really, this past September.