Robert Downey Jr. is giving his late father the ultimate tribute with the new documentary, "Sr."

Downey Jr.'s father, Robert Downey Sr., was an actor, writer and director most well-known for writing and directing the 1969 satirical comedy "Putney Swope." While Downey Jr. wanted the documentary to be an intimate portrait of his father, his dad previously had plans for a completely different kind of movie.

"The key point in this is when he goes, ‘OK, I think we should split into two camps: The (expletive) movie and the one I'm gonna make,'" recalls Downey Jr., laughing. "I just go, ‘Man, hats off to you, Pops."

The "Iron Man" star had a huge role in the making of the documentary, giving viewers the sense that they're watching a private home movie of the family. Working on the documentary together gave the father-son duo a better understanding of each other, with Downey Jr. saying "my dad and I are pretty flawed dudes."

Robert Downey Jr. and Sr. at Time 100 Gala

Robert Downey Jr.'s newest film is a documentary honoring his late father, Robert Downey Sr. (Stephen Lovekin/Getty Images)

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"It was a way to put something between us in our own relationship and closure. I didn’t know that it would be the quickest way to the heart of things," Downey Jr. told The Associated Press. "It’s like a little string you pull at, you know. And it winds up pulling you into a rabbit hole that I kind of needed to go down in order to process and ingest the totality of our relationship."

Downey Sr. died in July 2021 at the age of 85, due to complications with Parkinson's disease. His final days are featured in the documentary, something Downey Sr. wanted to be included.

For Downey Jr., his intention going into the movie was to get a better understanding of his father and their shared demons and to take advantage of their opportunity to make one last movie together. The younger Downey's introduction to the film industry was walking around on his father's sets, even getting his first role in his dad's 1970 comedy "Pound," at the age of 5.

"I have pretty good recall for the entirety of this incarnation, for better or worse," Downey Jr. said. "Those films and projects, I have very clear memories of that. I can still see the Mounds bar that was being handed to me. It was my first prop I ever had to deal with."

Downey Jr. considers it a good thing he was introduced to the industry at such a young age, saying he "had the advantage of it already feeling natural before I came into that quote-unquote industrialized version of entertainment."

Robert Downey Jr. Iron Man

Robert Downey Jr. says that while he's known as Iron Man now, he was known as Bob Downey's kid for the longest time. (Alberto E. Rodriguez/WireImage)

While he might be known as Tony Stark, Sherlock Holmes or Charlie Chaplin today, he explained that he was known as "just Bob Downey’s kid for a long time." Many of the films Downey Sr. made were considered part of the counterculture and out of the mainstream, giving him the reputation of being a skeptical nonconformist.

In watching the documentary, it is clear the father and son had an immense love for one another, but Downey Sr.'s affinity for everything outside the mainstream made it difficult for Downey Jr. to get a compliment from his father about one of his own movies.

"I hate to say it, but he was a bit of a snob. Susan [Downey Jr.'s wife] and I did a couple Sherlock movies. He was like, ‘Cute.’ I did a bunch of the Marvel stuff and he goes, ‘Uh uh. Yeah, bomb, bomb. Jokes. Funny robots. I get it.’ I went, ‘Hm. Wow. OK,’" Downey Jr. said. "I remember that he thought ‘Less Than Zero’ was good. He thought ‘Chaplin’ was too episodic. And he really liked that German song I sang when I was 15."

Although there are many similarities in their respective lives, such as their love of filmmaking and their struggles with drug addiction, there is one thing Downey Jr. doesn't think he inherited from his dad, saying, "I did not get his wildly optimistic ongoing super-curiosity," something his wife Susan disagrees with.

"You absolutely have your observation of the world. You’re hyper-aware of what’s going on around you and comment on it, much as Sr. did," she said. "And I think you deal with anything uncomfortable through humor. This is a secret power that you guys have. There’s wonderful things that come with that, and then there’s probably avoidance patterns that are kept up because of that."

On those ’70s films, Downey Sr.’s cocaine use was rampant, an environment that surely had an influence on Downey Jr.’s own struggles later with drug addiction. It’s a point that Downey Jr. raises in the film: "We would be remiss not to discuss its effect on me," Downey Jr. tells his father. He replies: "I would sure love to miss that discussion."

Robert Downey Jr. and Susan at Academy Museum

Robert Downey Jr. relates to his father's path of struggling with addiction until finding stability with his second wife. He found stability with his wife, Susan Downey. (Emma McIntyre/WireImage)

Both Jr. and Sr. went through a period of struggling with addiction, but as shown in "Sr.," both men were able to reach sobriety through finding stability in their families. Downey Jr. remembers noticing a change in his father when he got together with his second wife, Laura Ernst, who died in 1994, and then his third wife, Rosemary Rogers.

"I can relate to that, too, up until this current administration, the never-ending Susan Downey empire," Downey Jr. said. "I just have a lot more gratitude."

Since both father and son worked in the entertainment industry, it's no shock they both have a love of movies, and watching them together was a way for them to bond and connect. According to The Associated Press, the last film they watched together was "Walk Hard," and they laughed the whole time.

As his first acting job was with his father, Downey Jr. felt very comfortable on that set, something he has found with other directors since, calling Richard Attenborough "a super wise, loving grandfather" and saying Jon Favreau "was like a brother."

"It’s very odd, too, because we’re doing this film with director Park (Chan-wook) now called 'The Sympathizer,' where I’m doing a lot of different characters. It's not experimental at all. It's very well-fleshed out. But it's kind of reminding me of the Sr. experience," said Downey Jr. "You get dressed up, you try a character, and we're going to film it… so I'm still working for Dad."

Robert Downey Jr. and dad

Robert Downey Jr. says he feels like he's still working for his dad. (Larry Busacca/WireImage)

"Sr." is set to debut Friday on Netflix.