John Waddington, best known as the founding guitarist for the pioneering experimental post-punk band the Pop Group, has died. The band’s Twitter account announced Waddington’s death, writing, “John Waddington – former guitarist and founding member of The Pop Group – has passed away. An influential musician, and an integral member of the group, John contributed to some of the band’s most iconic recordings.” No cause of death was given. He was 63.

Waddington’s death closely follows that of Pop Group frontman Mark Stewart, who died in April at age 62.

After fronting his own band the Boyfriends as a teenager, Waddington joined the Pop Group in Bristol in 1977 at age 17. He played guitar on the first two Pop Group albums, 1979’s Y and 1980’s For How Much Longer Do We Tolerate Mass Murder?, helping to develop the band’s wildly noisy dub-inflected avant-funk sound. He soon played on records by the post-punk supergroup New Age Steppers, as well as Maximum Joy, Playgroup, African Head Charge, and Judy Nylon. In the ’90s, Waddington joined the guitar-pop band Perfume. He played bass on “Take What You Take” from Lily Allen’s 2006 debut Alright, Still.