Ray Thomas, the singer and multi-instrumentalist for the Moody Blues, died on Thursday (January 4) after a multi-year battle with prostate cancer. He was 76.

Moody Blues multi-instrumentalist Ray Thomas has tragically died just months before his long-awaited induction into the Rock & Roll Hall of Fame. He had just turned 76 on Dec. 29.

Thomas added a key flute solo to their signature hit “Nights in White Satin,” as Days of Future Passed soared to platinum-selling status in the U.S. He later confirmed that he and Pinder sang backup vocals on the Beatles‘ “I Am the Walrus,” and that he played harmonica on “Fool on the Hill,” from Magical Mystery Tour.

Esoteric and Cherry Red Records confirmed his death this morning, saying Thomas “passed away suddenly at his home in Surrey on Thursday.” Thomas revealed, via his personal website, that he’d been diagnosed with inoperable prostate cancer in 2013, but no official cause of death was initially mentioned.