LOS ANGELES — While starring in films like "Selma" and "Lee Daniels' The Butler," actor David Oyelowo discovered a new passion: directing.

Oyelowo was inspired to step behind-the-camera after learning different nuances of the craft from respected directors like Ava DuVernay and Will Gluck. His desire to act and direct in the same movie grew even more after seeing successful efforts from his friends Nate Parker in "The Birth of a Nation" and Joel Edgerton in "The Gift," as well as Mel Gibson, who won an Oscar for best director for "Braveheart."

For years, Oyelowo picked their brains to feel confident enough to make a leap of his own. The actor's directorial debut, "The Water Man," arrives in theaters Friday. The film was produced by Harpo Films with Oprah Winfrey serving as executive producer.

Oyelowo said he learned about having a grasp on the movie's theme from DuVernay. He credits Gluck with teaching him the importance of a director capturing all of the elements in a film: wardrobe, photography, editing — as well as each actor's performance.

"I've sort of had my own film school through working with several great directors," said Oyelowo, who stars in the film with Rosario Dawson. "(Directing) came as a byproduct of my acting career. I wanted to direct because I've been around some of the best people in the world."

"The Water Man" tells a story about a hopeful boy named Gunner who is looking to save his severely ill mother, played by Dawson. The boy and his friend venture into a remote forest to search for a mythical figure, who Gunner believes carries the secret to everlasting life.

Oyelowo said he was drawn to the script because the story reminded him of his favorite fantasy films like the '80s classics "The Goonies" and "Gremlins." 

"Those films have some heavier themes where kids are still involved," said Oyelowo, who plays Gunner's father, Amos. "This film has that sort of a young person in jeopardy theme, which I loved growing up." 

Oyelowo said the film's driving force is Gunner, played by 13-year-old Lonnie Chavis, who stars on the NBC hit drama series "This Is Us."

"It's the power of sacrificial love," Oyelowo said. "You have this kid who is prepared to risk everything to save his mother. You have this father who is prepared to save his son. You see a family who is imperfect, but they have a love that I think is pretty much perfect. They define sacrificial love. She's ill but she doesn't think about herself. She's thinking about the relationship between her son and husband."

This image released by RLJE films shows Lonnie Chavis, left, and David Oyelowo in a scene from “The Water Man,” a film by David Oyelowo. (Karen Ballard/RLJE films via AP)

After reading the script, Dawson said she related to Gunner's character, who has to face his parent's mortality just like her. The actor said she learned that her father was diagnosed with pancreatic cancer shortly after she landed the role of Mary, who is battling leukemia in the film. 

Dawson said she had some tough times while filming as she dealt with her father's health. But she said her role gave her the opportunity to channel everything that was going on in real life to help deliver a relatable story.

"I had to self motivate a strength that just wasn't there," said Dawson. As her father was starting chemotherapy treatments, she sent him a photo of her balding character in solidarity.

"It was acknowledging the limitations and building it into a performance in a way I think was important for me to represent with dignity," she continued. "It's such a vulnerable state to be in when you're that ill and really dependent on other people."

Dawson said Oyelowo — whose late father battled cancer — helped her along the way. She said Oyelowo made things easier for herself and the rest of the crew, calling him a consummate actor and storyteller.

"He was clear about his vision and tone," she said. "We didn't have a whole lot of time in the world, but it still felt like we did. He really allowed us to play and find our moments, find our pauses and our bursts of energy. He's such an actor's actor."

This image released by RLJE films shows Lonnie Chavis, left, and Rosario Dawson in a scene from “The Water Man,” a film by David Oyelowo. (Karen Ballard/RLJE films via AP)

Chavis said Oyelowo helped him pull into the emotional state of Gunner. 

"There was a scene where I had to climb this big log, and I was really afraid of heights at the time," Chavis remembered. "So Mr. David pulled me aside and he gave me a personal story about his life … something to tap into my own life. He was doing all this for the love and the passion that he had for the film."

In return, Oyelowo said Dawson and Chavis made him look good as a director. 

Oyelowo said he wants to direct more projects, if he can juggle that with his busy acting career. He likes mixing reality and fantasy, but he's also passionate about telling African stories. 

"I think there are just some incredible stories that are not sequels or remakes," Oyelowo said. "In some ways, they've slept on Africa as a producer of great stories and great content. I really want to be a part of seeing those kind of stories in a global presence."