The Grateful Dead co-founder, guitarist, and singer Bob Weir has died. He was 78 years old.

Weir's representative, Samantha Tillman, issued a statement confirming his passing, writing that "he transitioned peacefully, surrounded by loved ones, after courageously beating cancer as only Bobby could." Unfortunately, the musician ended up dying due to existing lung issues, despite overcoming the 2015 cancer diagnosis.

Along with Jerry Garcia, Weir served as the Dead's co-lead singer, operating in a more subtle light than the iconic Garcia – yet he was dubbed a "stealth machine," due to his meaningful contributions, by bassist Phil Lesh (who sadly died last year).

Born in October 1947, Weir began playing guitar at age 13 and went on to meet Garcia on New Year's Eve, 1965. They decided to start a band together, forming under the name Mother McCree's Uptown Jug Champions. In time, they evolved from an acoustic band into electric rockers Warlocks... before re-naming to The Grateful Dead. In 1972, Weir became co-lead vocalist, following the passing of fellow founding member Ron "Pigpen" McKernan.

Following Garcia's death in 1995, Weir played with spin-off bands The Other Ones and The Dead, keeping the group's music very much alive. Beyond his primary presence in The Grateful Dead, Weir released solo albums, formed a namesake band, and another one bearing the name Bobby and the Midnites.

In more recent years, Weir was a part of Dead & Company, alongside John Mayer and additional Grateful Dead alumni. He was eager to keep the band's legacy going as the Dead marked its 50th anniversary in 2015, "often [speaking] of a 300-year legacy, determined to ensure the songbook would endure long after him," his family's statement noted.