Nick and Aaron Carter's father Robert Gene Carter passed away suddenly at age 65 Tuesday.
The 37-year-old Backstreet Boys singer and his 29-year-old brother and fellow pop star announced the news on Twitter Wednesday.
"I am heartbroken to share the news that our father, Robert, passed away last night..." Nick wrote. "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."
"My heart is Completly shattered I'm in shock and I loved my dad so much. #RIP DADDY I Love You," Aaron tweeted.
"My heart is broken," he wrote on Instagram. "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 #BobCarter #RIP #MyDaddy."
Robert also is survived by wife Ginger Elrod and their son, Kaden, Nick's mother, Jane, Aaron's twin Angel Carter and daughter Bobbie Jean, 35, and another daughter, Virginia, from a previous relationship.
Nick's sister Leslie Carter died at age 25 in 2012.