After news of Lou Reed's death broke early Sunday, many celebrities took to Twitter to mourn the loss of the Velvet Underground frontman and rock icon.
"The world has lost a fine songwriter and poet… I’ve lost my ‘school-yard buddy,'" wrote Reed's Velvet Underground co-founder John Cale on Facebook.
Lou Reed died at the age of 71. It's not immediately clear why, but he underwent a liver transplant operation at the Mayo Clinic in Cleveland in May.
Among those lamenting the loss of the unforgettable "Wild Side" singer were Kevin Smith, Jon Cryer, Olivia Wilde, John Cusack, Flea and Nikki Sixx.
Read what they had to say on social media below:
Kevin Smith: Mr LOU REED had himself a dream: Velvet the underground & change the music scene. Now he's up & gone away. #RIP Lou Reed, an un-Perfect Day.
John Cusack: Lou Reed RIP - always inspired by him - terrible news - only knew him through his art -a great - a singular poet -
Flea: I love Lou reed so much. Always
Jenna Elfman: We'll miss ya, Mr. Lou Reed #RIP
John Taylor: one of the great ones. Thanks for the music Lou
Iggy Pop: Devastating news.
Samuel L. Jackson: R.I.P. Lou Reed. Just met at the GQ Awards. The music of my generation. Still Relevant!
Olivia Wilde: Damn. Lou Reed. Damn.
Elijah Wood: May you forever walk on the wild side, Lou Reed. Terribly sad to hear of your passing.
Jon Cryer: "Walk on the Wild Side" is easily one of the ten best pop singles of the 20th century.
Paul Feig: Thanks to Lou Reed for being a true original. So glad the world has his recordings. I know what I'll be doing the rest of the day.
Nikki Sixx: RIP Lou Reed.Thank you for your beautiful/dark lyrics/music and stance on life. You inspired me from my teenage years right up till today.
Rachel Nichols: Sad news. RT @AP: BREAKING: Punk-poet, rock legend Lou Reed dies at age 71 of liver-related ailment