During an interview, Robert De Niro shared personal stories about his deceased father, Robert De Niro Sr., who happened to be openly gay. In his tell-all with Out magazine, the award-winning actor detailed how his new documentary intends to honor his dad's life, artworks and legacy.

"I felt I had to. I felt obligated," De Niro explained how the decision to create the documentary has been brought about. "It was my responsibility to make a documentary about him. I was always planning on doing it, but never did. Then Jane Rosenthal, my partner at Tribeca (Enterprises), said, 'We should start doing that now.' It was not intended to be on HBO. It was just something I wanted to do."

The documentary is entitled 'Remembering the Artist: Robert De Niro, Sr.". It is scheduled for airing on HBO this coming June 9. One of the revelations highlighted in the documentary was the conflict that De Niro Sr. went through regarding his homosexuality.

"Yeah, he probably was, being from that generation, especially from a small town upstate," De Niro mentioned. "I was not aware, much, of it. I wish we had spoken about it much more. My mother didn't want to talk about things in general, and you're not interested when you're a certain age. Again, for my kids, I want them to stop and take a moment and realize that you sometimes have to do things now instead of later, because later may be 20 years from now - and that's too late."

The actor's dad passed away more than 2 decades ago. Nevertheless, the late NYC artist's legacy, including his final home and art studio, has been carefully preserved by his son. De Niro explained, "It was the only way to keep his being, his existence alive. To me, he was always a great artist."