Monkees singer and bassist Peter Tork has died at the age of 77.

Tork’s sister Anne Thorkelson confirmed his death, according to the Washington Post

Tork passed away on Feb. 21 and was diagnosed with a rare cancer on his tongue in 2009. Details have not been released about the cause of his death.

Tork was a member of the pop group that became a sensation with teeny-boppers in the 1960s. He continued to play with the band during reunion tours.

Growing up, he lived in Mansfield, Conn. and went to E. O. Smith High School.

The Monkees had their own TV show and sold 35 million albums in 1967, according to the Washington Post. Some of their hit number one songs include “Daydream Believer,” “Last Train to Clarkssville, and “I’m a Believer.”

Other members of the Monkees include Michael Nesmith, Micky Dolenz and Davy Jones.