Backstreet Boys singer Nick Carter has paid tribute to his "baby brother" Aaron after he was found dead.
The singer, 42, wrote on Twitter that his "heart is broken" and uploaded several photos of the pair in their younger years.
"Even though my brother and I have had a complicated relationship, my love for him has never ever faded," he posted on Sunday.
"I have always held on to the hope that he would somehow, someday want to walk a healthy path and eventually find the help that he so desperately needed."
He added that "addiction and mental illness are the real villains here", signing off the post: "I love you baby brother."
Carter, 34, was found dead in a bath at his Los Angeles home on Saturday, according to reports.
He was discovered by a house sitter at around 11am that day, but attempts to resuscitate him were unsuccessful, local authorities said.
The singer, rapper and actor, was best known for his songs Aaron's Party (Come Get It), I Want Candy, and his appearances on the TV shows Lizzie McGuire and Dancing With The Stars.
In 2012, the Carter brothers' sister Leslie died after falling in the shower, with authorities ruling she died from an overdose of prescription medication.
In 2017, he attended rehab after being arrested on suspicion of driving under the influence and marijuana charges.
He revealed in a 2019 episode of the talk show The Doctors that he was taking medication for multiple personality disorder, manic depression and acute anxiety.
The same year, Nick Carter and his other sister Angel filed a restraining order against him over claims he threatened to kill Carter's pregnant wife and unborn child.
Attended rehab again this year
Earlier this year, he checked into rehab again in the hope of regaining custody of Prince, the son he shared with his fiance Melanie Martin.
Tributes flooded social media after news of his death broke.
Actress and singer Hilary Duff, who played Lizzie McGuire, posted a tribute on Instagram, writing: "For Aaron - I'm deeply sorry that life was so hard for you and that you had to struggle in-front of the whole world.
"You had a charm that was absolutely effervescent… boy did my teenage self love you deeply. Sending love to your family at this time. Rest easy."
US boy band New Kids On The Block shared a black and white photo of Carter and wrote on Twitter: "We are shocked and saddened about the sudden passing of Aaron Carter.
"Sending prayers to the Carter family. Rest in peace, Aaron."
Anyone feeling emotionally distressed or suicidal can call Samaritans for help on 116 123 or email email@example.com in the UK. In the US, call the Samaritans branch in your area or 1 (800) 273-TALK