Following reports that Lou Reed died on Sunday, October 27, at the age of 71, droves of musicians expressed grief and paid tribute to the Velvet Underground co-founder on Twitter. As of press time, an official cause of death has not yet been revealed, but Reed’s literary agent, Andrew Wylie, told the New York Times he believed Reed’s passing was related to a liver transplant the singer-songwriter underwent earlier this year. Wylie added, “He was as great an artist as it’s possible to be in my opinion.”

Surviving VU member John Cale shared a simple but tender remembrance on Facebook, writing, “The world has lost a fine songwriter and poet… I’ve lost my ‘school-yard buddy.'”

David Bowie’s official Facebook posted a photo of Bowie and Reed together in 2007 with a caption that reads, “It is with great sadness that we report the death of Lou Reed who died today aged 71. (March 2, 1942 – October 27, 2013)… David Bowie said of his old friend: ‘He was a master.'”

Scroll down to read other heartfelt reactions to Reed’s sudden death, including an official statement from the Recording Academy, as well as tweets from My Morning Jacket’s Jim James, Franz Ferdinand’s Alex Kapranos, and Sonic Youth co-founders Kim Gordon and Lee Ranaldo. Also be sure to read SPIN’s lengthy 2008 interview with Lou Reed, in addition to our critical evaluation of the icon’s most essential works.

The Recording Academy’s official statement regarding Lou Reed’s death: Grammy winner Lou Reed was an exceptionally gifted singer, songwriter, and musician who has had a profound impact on rock music and our culture. Both his work with the Velvet Underground and his solo efforts are legendary, introducing avant-garde rock to the mainstream. His uniquely stripped down style of guitar playing and poetic lyrics have had a massive influence across many rock genres, including punk and alternative. We have lost a true visionary and creative leader, and his groundbreaking work will forever hold its rightful place in music history. Our thoughts and condolences go out to his family, fans and those he inspired.

Lou Reed is the reason i do everything i do

— Julian Casablancas (@Casablancas_J) October 27, 2013

RIP Lou Reed. you made the world a better place. we are forever grateful.

— jim james (@jimjames) October 27, 2013

RIP Lou Reed. Irreplaceable.

— Lee Ranaldo (@leeranaldo) October 27, 2013

So sorry to hear of Lou Reed s passing this is a huge shock!

— Kim Gordon (@KimletGordon) October 27, 2013

I will remember Lou Reed fondly, particularly the time I rode past him in full cycling gear on the West Side Highway. He looked good.

— alex kapranos (@alkapranos) October 27, 2013

“I’m an artist and I can be as egotistical as I want to be” RIP Lou Reed

— Guns N’ Roses (@gunsnroses) October 27, 2013

Lou Reed, R.I.P. I did the Jools Holland show with him last year and we yucked it up. I didn’t know he was ill…. http://t.co/enOpYpnGlg

— Nile Rodgers (@nilerodgers) October 27, 2013

R.I.P Lou Reed – VU was a big influence when weezer was being formed, and Ric Ocasek told us cool stories of his friendship with him.

— weezer (@Weezer) October 27, 2013

I love Lou reed so much. Always

— Flea (@flea333) October 27, 2013

Sunday Mourning–we’re going to miss you, Lou.

— Sub Pop Records (@subpop) October 27, 2013