Celebrities like John Mayer and Wiz Khalifa flocked to Twitter to share their grief over the death of rapper-producer Mac Miller.

He was 26. He was pronounced dead at his Studio City, California, home, the Los Angeles County Department of Medical Examiner-Coroner said in a statement to people.com.

The cause of death is yet to be determined, but a source said the rapper had gone into cardiac arrest after appearing to suffer a drug overdose.

Miller, born as Malcolm James McCormick, long battled substance abuse issues, particularly in the wake of his split with longtime girlfriend and singer Ariana Grande. In May, he was arrested on DUI and hit-and-run charges.

Recommended Read: Rapper Mac Miller passes away at 26

Chance the Rapper was among those who offered his thoughts, revealing that Miller played a major role in helping launch his career, reports people.com.

Mayer, who played guitar on the track Small worlds from Miller's latest album Swimming, posted a blank image on Instagram in tribute. "I'm so sad you couldn't stay, Mac. I'm so terribly sad."

https://www.instagram.com/p/BncKT3Hn9Jl/?taken-by=johnmayer

G-Eazy posted a photograph of the two with a moving caption for the late rapper.

"Completely devastated and heartbroken. I'm at a loss for words. Mac you were like a brother to me and were there for me in the hardest of times, especially this summer. I can't believe this is real," he wrote.

https://www.instagram.com/p/BncSqt9nwIL/?taken-by=g_eazy

"Please tell your friends and the people you care about you love them life is so fucking fragile. You will be missed and your music will live on forever through the millions of people you touched. Thank you for all you gave us, love you bro."

DJ Khaled and singer Khalid also tweeted messages of love to the late star.

https://twitter.com/djkhaled/status/1038194361102753793