Tragedy struck, as Swedish DJ and musician Avicii has died.
His real name waws Tim Bergling.
He was only 28 years old.
His fans, who are beyond numbering and live all over the world, are in mourning at this sudden, unexpected loss.
Those who knew him best -- his friends and those who worked with him, particularly within the field of music, are expressing their shock and sorrow.
Taking to Twitter, they are remembering their late friend and colleague and expressing their heartwrenching grief.
These are their tweets:
Liam Payne is of course world-famous as a member of One Direction.
Calvin Harris is a DJ, an underwear model, and is best known for being Taylor Swift's ex-boyfriend.
Ruby Rose clearly knew Avicii personally. She is best known for roles on shows like Orange Is The New Black and Dark Matter, and will appear in the upcoming film, The Meg.
Joal Thomas Zimmerman is best known by his stage name, deadmau5. The "5" numeral is pronounced like the letter "S." He is a producer, DJ. musician, and composer. He does a lot with house music and with EDM.
Justin David Blau is better known by his stage name, 3LAU, is a DJ and EDM producer.
Kevin McHale is formerly of the boy band known as MLT, he is best known for having played Artie on Glee.