Country Joe McDonald — the legendary lead singer and co-founder of 1960s psychedelic folk rock band Country Joe and the Fish, best known for the anti-Vietnam War anthem “I-Feel-Like-I’m-Fixin’-to-Die Rag” — has died … TMZ has learned.

Sources with direct knowledge tell TMZ … the Woodstock icon died Saturday evening. Details surrounding his death are currently unclear.

McDonald, born Joseph Allen McDonald, became one of the defining voices of the 1960s protest movement. As frontman of Country Joe and the Fish, he helped shape the San Francisco psychedelic scene during rock’s most politically charged era.

His 1969 Woodstock performance, which was complete with the crowd-wide “Fish Cheer,” remains one of the festival’s most unforgettable moments, cementing his place in counterculture history.

Beyond Woodstock, McDonald continued performing for decades, blending folk, rock and activism. He was known for supporting veterans and speaking out on social issues long after the height of the protest era faded.

Over a career that spanned more than half a century, he remained closely tied to the music and message that first made him famous.

Country Joe McDonald was 84.