Tomorrow on a special episode of 20/20, Bobby Brown will sit down with Robin Roberts in his first sit-down interview since his 22-year-old daughter Bobbi Kristina Brown died in July of last year.

During the interview, he talks about how similar the death of his ex-wife, Whitney Houston was to that of his daughter. "The same thing that happened to my daughter, it happened to Whitney," he tells Robin.  "The hardest thing I had to do in my life was tell my daughter to let go," he says, breaking down in tears. "My baby's gone."

Bobbi Kristina was found face-down in her bathtub. Her mother had also been found unresponsive in a Beverly Hilton room bathtub back in 2012. Whitney Houston was 48 when she passed.  Bobbi Kristina's death happened three years later. It was six months after she was found and put into a medically induced coma before she was taken off life support. Bobbi's autopsy confirmed that she died as a result of her immersion in the water, as well as drug intoxication- including marijuana and alcohol, along with a sedative medication that was used to treat anxiety.

Bobbi Kristina's boyfriend, Nick Gordon was accused by her family for her death. Bobby Brown has written a tell-all book, Every Little Step: My Story, which, according to Radar Online, contains revelation of what he believes caused his daughter to become unresponsive.

Four days before she was found in the bathtub, she had been in a head- on car crash. "While we weren't discounting the possibility that Nick had something to do with Krissi's incident in the bathtub, we aso wondered whether the car accident she had been involved in just four days before she was found in the bathtub might have had something to do with her brain injuries," Brown writes. "We asked the doctors whether she could have suffered some type of brain trauma or hemorrhage that didn't present itself until four days later, resulting in the bathtub incident, but the doctors couldn't really give us definitive answers."

According to a Us Weekly source, Bobby had a hard time accepting that his daughter wasn't going to come back. "Their last interaction is not the last one he wants to have with his daughter," they said.

Bobby Brown made a statement back on July 27^th, the day after Bobbi Kristina passed. He told ET, "Krissy was and is an angel. I am completely numb at this time. My family must find a way to live with her in spirit and honor her memory. Our loss is unimaginable," he said. "We thank everyone for the prayers for Krissy and our family as we mourn my baby girl."

Here's the preview of the special 20/20 episode which premieres on Tuesday June 7^th 9/8c on ABC.