Robert De Niro's father is the subject of a new documentary that highlights his role in the New York City abstract expressionist art movement, according to Reuters.

De Niro, 70, attended the Sundance Film Festival Sunday in Park City, Utah, to premiere "Remembering the Artist Robert De Niro, Sr.," a HBO documentary about his father, who emerged alongside contemporaries including Jackson Pollock and Willem de Kooning.

Robert Sr. grew up in a conservative Italian-American family in New York and married fellow artist Virginia Admiral, with whom he had one child. The marriage didn't last long, though the couple reportedly split amicably.

Abstract expressionism emerged after World War II and is said to be the first notable American artistic movement to define a stylistic era. While Robert Sr.'s works emerged during that time period, his style is not described as abstract expressionist but instead as figurist, often depicting still life "in simple setups with no pretension," as described in the documentary, Reuters reports.

I don't know what any of that means. But it sounds pretty important.

Robert Sr. reportedly became increasingly disconnected from the abstract expressionist movement, inspired more by early 20th century French artists such as George Roux, Pierre Bonnard and Henri Matisse. Robert Sr.'s works included vibrant and intense color palettes and fluid silhouettes, Reuters said.

"He was very clear about what he thought was art and what he liked, and yet at the same time he was generous, people can appreciate things, it doesn't matter if the aesthetic can be different from yours," De Niro said, at the film's premiere. "He didn't feel that certain things art-wise were art. It was another thing that wasn't enough for him, and his own style as you see was always the same. It varied some but not a lot."

De Niro experienced his father insights though the older man's journals, which revealed his struggles with his relationship with God and his attempts at coming to terms with being homosexual.

De Niro said his father, who died in 1993 from prostate cancer, may never not have resolved those issues.

De Niro said he wanted to bring the documentary to Sundance, the top U.S. independent film festival, to make sure the works and memory of his father got their proper attention.

"We were really thrilled that it was chosen for Sundance because it separates from having it at Tribeca and we see Bob's father's works on its own in a different setting than you would in New York," producer Jane Rosenthal said.

The documentary explores not only Robert Sr.'s career, but his role as a loving father. Though De Niro has said he had a very close relationship with his dad, but felt his father was resentful that his son's career took off in a way that his own did not.

De Niro said the documentary -- scheduled to run on HBO this summer -- is an homage to his father, whose paintings are still shown in galleries around the world. It also serves as a family memory, he said.

"I realized how important it is for children to appreciate certain things (their parents) want to share with them," an emotional De Niro says in the film.

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