Hip-hop legend Dr Dre is in an intensive care unit in Los Angeles after suffering a brain aneurysm, according to reports.
The 55-year-old N.W.A. star is said to have been rushed to hospital in an ambulance on Monday (local time).
Dr Dre is in a "stable and lucid condition" as doctors do tests at Cedars-Sinai Medical Center, according to gossip outlet TMZ.
On Twitter, tributes are pouring in for the rapper and hugely successful producer.
"Send your love and prayers to the homie Dr Dre," tweeted former N.W.A. co-star Ice Cube.
"Prayers up for Dr Dre and his family for healing and strength over his mind and body," added Missy Elliott.
LL Cool J was more upbeat, tweeting: "Dre is recovering nicely."
Quincy Jones tweeted: "Beloved Dr Dre, love you man, like my own son! After going through two aneurysms myself, I'm believing and trusting that you will come out stronger than ever before! Here for you - whatever you need."
NBA stars Dwyane Wade and Magic Johnson, actor Terry Crews along with rappers TI and G-Eazy are among the other stars sending love and prayers to Dr Dre on Twitter.
Dr Dre, born Andre Romelle Young, has won six Grammys and was said to have become hip-hop's first billionaire after Apple bought his Beats headphone and music streaming service in 2014.