Robert De Niro produce a documentary about his late father called "Remembering the Artist: Robert De Niro Sr" that airs on HBO Jun. 9. The award-winning actor's father is a NYC artist and happened to be openly gay. E! reported that the documentary will showcase all of his father's artwork and shed light on his legacy.

"I felt I had to. I felt obligated," De Niro says in an interview with Out magazine regarding the film. "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."

Reportedly, Robert De Niro has discussed the difficulties his father faced coming to terms with his homosexuality.

"He probably was (conflicted about his sexuality)," the Taxi Driver actor told OUT Magazine. "Being from that generation, especially from a small town upstate (in New York).

"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 realise that you sometimes have to do things now instead of later, because later may be 20 years from now - and that's too late," he added.

"We were not the type of father and son who played baseball together, as you can surmise," De Niro recalls his relationship with his father. "But we had a connection. I wasn't with him a lot, because my mother and he were separated and divorced... He was absent in some ways. (But) he was very loving. He adored me... as I do my kids," the actor, 70, described.

According to The Independent, the actor continues to preserve his father's art studio and final resting place in SoHo, New York.

"It was the only way to keep his being, his existence alive. To me, he was always a great artist."