Demi Lovato's former boyfriend and colleague Joe Jonas has sent his support after the singer was taken to hospital following a suspected overdose.
Emergency services were called to the 25-year-old singer's Hollywood home on Tuesday, and a representative for the star has said she is "awake and with her family".
Jonas wrote: "Like all of you I am thinking of @DDLovato right now. She needs our prayers and support. We all know how strong you are Demi. #prayfordemi."
His brother and former Jonas Brothers co-star Nick Jonas, who also toured with her, tweeted: "Like all of you I am reeling at the news about Demi. All of us love her and need to pray for her to get well. She is a fighter. #prayfordemi."
Rapper Macklemore performed his song Otherside, about his battle with addiction, on stage in Massachusetts and dedicated it to Lovato.
In a video clip shared on Twitter, Macklemore said: "I just wanna send prayers and my thoughts and love out to Demi Lovato, who I heard about, and I know, when we have this disease of addiction, that ties us addicts together, and that's my sister in recovery."
Following the news of Lovato's reported overdose, a statement from her representative said: "Demi is awake and with her family who want to express thanks to everyone for the love, prayers and support.
"Some of the information being reported is incorrect and they respectfully ask for privacy and not speculation as her health and recovery is the most important thing right now."
Other celebrities have continued to rally around Lovato.
Lady Gaga wrote on Twitter: "We should all wrap our arms of love around Demi Lovato. I am so happy you're alive. Thank God."
Boy George wrote: "Wishing @ddlovato a speedy recovery. Let go, let GOD. The universe wants you here child. #recover #Recovery #Love."
Bruno Mars wrote: "Sending love and prayers to Demi Lovato." Ariana Grande simply tweeted "I love u" to Lovato.
Chat show host Ellen DeGeneres tweeted: "I love @DDlovato so much. It breaks my heart that she is going through this. She is a light in this world, and I am sending my love to her and her family."
"Poor beautiful spirit @ddlovato I hope she's ok, and that she makes a full recovery soon," Lily Allen tweeted.
Kelly Osbourne has urged fans of Demi Lovato to "show love and pray for her".
The TV star spoke of her own experiences with addiction and said people need to support the musician, who has spoken openly about her battle with alcohol and substance abuse.
Osbourne told ITV's Loose Women: "I will never speak on behalf of Demi because that wouldn't be right.
"I can only share about what I've been through and what I know from myself. Relapse is one of the hardest things we face as an open addict who has gone through the programme and turned their life around.
"People need to know rehab doesn't fix you, it just helps you to get yourself on the right track. You're never fixed. You spend your whole, entire life doing everything you can to never pick up and use again.
"Addiction does not discriminate. It takes hold of anyone and everyone if it can,"she said.