Backstreet Boys singer Nick Carter and his younger brother Aaron have spoken of their heartbreak following the sudden death of their father Bob Carter.

The 65-year-old died on Tuesday (16 May) night in Florida. While the cause of death has not been revealed, his passing was believed to be unexpected with both of his sons performing at the Wango Tango concert in Los Angeles at the time, Mail Online reports.

In an emotional post on Twitter Aaron wrote: "My heart is Completly (sic) shattered I'm in shock and I loved my dad so much. DADDY I Love You. This is the last pic I have my dad."

In a second tribute on Instagram he described his father as his superhero. "My heart is broken, We are so hurt we lost you poppa way too soon. You were never human to me, you were always my real life super hero."

Nick, 37, tweeted: "I am heartbroken to share the news that our father, Robert, passed away last night ...

"While we learn more about the cause of death, and begin the grieving process, we ask that our privacy be respected at this difficult time," he continued.

The family had a long history of domestic tension with Nick revealing in 2015 that he was estranged from his parents Bob and June. "I haven't seen them in maybe seven or eight years," he told his band mates in their documentary The Backstreet Boys: Show 'Em What You're Made Of.

Describing his childhood as a volatile household, he said: "It was a house full of fear for me. We would be little kids and we would hear mom and dad screaming at each other.

"They'd constantly be drinking and fighting and we'd hear guns go out the window shooting. Not shooting at each other. They always fought over money," he added.

After the brothers found international success as singers, money caused a further split in the family as Jane who managed Aaron was accused of stealing money from him.

"Every show we did, we would probably make about maybe $40,000, $50,000 a show. And it was all gone," Aaron said in a 20/20 interview.

After cutting their parents out of their lives, the family were struck by tragedy in 2012 when Nick and Aaron's sister Leslie died of a suspected prescription pills overdose at the age of 25.