Graham Nash has written a tribute post to his late musical collaborator David Crosby.

After the Stills & Nash singer was revealed to have died on Thursday, his bandmate Graham Nash took to Instagram confirming the news and paying tribute to the late musician.

The legendary rock singer and son of Oscar-winning cinematographer is believed to have passed away after suffering a heart attack. He was 81.

“It is with a deep and profound sadness that I learned that my friend David Crosby has passed. I know people tend to focus on how volatile our relationship has been at times, but what has always mattered to David and me more than anything was the pure joy of the music we created together, the sound we discovered with one another, and the deep friendship we shared over all these many long years,” Graham wrote. “David was fearless in life and in music. He leaves behind a tremendous void as far as sheer personality and talent in this world.”

He continued, “He spoke his mind, his heart, and his passion through his beautiful music and leaves an incredible legacy. These are the things that matter most.

“My heart is truly with his wife, Jan, his son, Django, and all of the people he has touched in this world.”

Stephen Stills, who joined the pair later to create Crosby, Stills, Nash & Young, also issued a statement on Graham’s death obtained by Variety.

“I read a quote in this morning’s paper attributed to composer Gustav Mahler that stopped me for a moment: ‘Death has, on placid cat’s paws, entered the room,’” he said. “I shoulda known something was up.”