Actor-director Robert De Niro on Sunday attended the premiere of a film at the Sundance Film Festival about his gay father.

De Niro attended the screening of the film Remembering the Artist: Robert De Niro, Sr.

The senior De Niro, who died in 1993 in New York at the age of 71, was an abstract expressionist painter of the post-World War II era.

The film documents the life of the painter thorough his son's eyes.

“I did this for him,” De Niro said during a Sundance panel following the film's premiere. “I wanted my younger kids – who were born after he died – to know what their grandfather did. I even kept his painting studio intact so they could see it.”

Director Perri Peltz explained that the film also explores “the entire art world of the time.”

HBO will broadcast the film in June.