Bobby Brown cries over Bobbi Kristina's death in candid TV interview

Bobby Brown broke down in tears in his first big TV interview since the death of his daughter Bobbi Kristina, insisting accepting her loss was "the hardest thing" he's ever done.

Bobbi Kristina Brown, the R&B singer's only daughter from his 14-year marriage to the late Whitney Houston, passed away on 26 July (15), almost six months after she was found face down and unresponsive in a bathtub at her Georgia home.

The circumstances surrounding the 22-year-old's death were eerily similar to those of Whitney's passing just three years earlier, in February, 2012, when she died from accidental drowning, heart disease and cocaine use at the Beverly Hilton hotel on the eve of the Grammy Awards.

Now, in a candid chat with U.S. reporter Robin Roberts, Bobby has opened up about his double heartbreak, revealing he felt helpless as his little girl lay in a medically-induced coma for months until her death.

"My baby's gone," the singer says in a preview of the interview, as his voice trembles and tears start to fall. "I thank God I'm still here. The hardest thing I had to do in my life was tell my daughter to let go."

Coroners ruled Bobbi Kristina's death was caused by the "immersion of face in water complicating mixed drug intoxication", and Bobby can't get over how similar the deaths of his ex-wife and their daughter were.

He later adds, "The same thing that happened to my daughter is what happened to Whitney."

Bobby also discusses his turbulent relationship with his superstar ex-wife during the 20/20 news special, joking, "I came into the marriage with money, and I left the marriage with nothing (following their 2007 divorce)."

The interview, which will air in the U.S. next week (begs06Jun16), emerges as Bobby prepares to become a father for the seventh time.

He and his wife of four years, Alicia Etheridge, are expecting their third child together, a sibling for son Cassius, seven, and daughter Bodhi, who will celebrate her first birthday in July (16), days before the first anniversary of Bobbi Kristina's death.

Bobby, 47, is also busy promoting his new memoir, Every Little Step, which is set for release later this month (Jun16).