Backstreet Boys singer Nick Carter has led tributes after the death of his younger brother and fellow star Aaron.
In a social media post Nick, 42, said the pair had a "complicated relationship" but his love had "never ever faded" for Aaron, who was 34.
Nick's band also dedicated a song to the younger Carter during a concert in London on Sunday evening.
Aaron's body was found at his California home on Saturday. No cause of death has yet been disclosed.
A statement from the late singer's team that day confirmed the news, promising more information when it was available.
US media reported that police found the lifeless body of the I Want Candy singer in the bath.
Carter, a former child star, sold millions of albums, having gained fame as an opening act for the Backstreet Boys in the late 1990s.
His brother Nick, a member of the American boy band, wrote online: "I will miss my brother more than anyone will ever know."
His post acknowledged that their brotherhood had not been without its tensions, which culminated in the elder Carter taking out a restraining order against his sibling in 2019.
Alluding to Aaron's well-documented struggles - which reportedly included multiple trips to rehab - Nick commented: "Addiction and mental illness are the real villains here".
Footage shared online showed Kevin Richardson, another member of the Backstreet Boys, acknowledging the news during a performance which went ahead on Sunday night.
He told a crowd at London's The 02 venue that the band had "heavy hearts because we lost one of our family members yesterday".
In the clip - posted by reviews website All That Dazzles - Richardson thanked fans for their support.
A silent Nick Carter was comforted by his bandmates, before the group went on to dedicate a performance of their song Breathe to their former touring companion.
Other stars - including Paris Hilton, Tyler Hilton and Hilary Duff, and bands New Kids on the Block and *NSYNC - have posted their own messages remembering the singer.