Kevin Costner was a defender of Whitney Houston, on and offscreen.

Costner, who co-starred with Houston in the 1992 romantic thriller “The Bodyguard,” reflected on his experience working with the pop icon during an interview on the “Armchair Expert with Dax Shepard” podcast released Monday.

The “Yellowstone” actor played bodyguard Frank Farmer, who was entrusted with protecting R&B singer Rachel Marron, played by Houston. Costner, who also served as a producer on the film, said he began to work closely with Houston on her performance after he sensed director Mick Jackson was “afraid” of her.

“I started to guide her. And I wasn’t trying to usurp my director, but I had made a promise to her,” Costner said. “I had promised Whitney that she’d be good in (the film). … I was always going to keep my promise to her.”

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Released in November 1992, “The Bodyguard” grossed $121.9 million at the global box office, while its Houston-led soundtrack went on to sell 18 million copies. The film earned a pair of Academy Award nominations for best original song (“I Have Nothing” and “Run to You”).

Costner also discussed building trust with Houston during the film’s production, which included creating a safe environment for the popstar on set.

“I said, ‘Look, you can’t have an entourage, but I’m going to take care of you if there’s a person important to you’ — turned out to be (assistant) Robyn Crawford,” Costner reflected. “I said, ‘Let’s have Robyn with you.’ But I said, ‘I don’t have one. You’re not going to have one.’ And that’s how we started. And I knew that it would never be the same for her when she left me.”

Costner added that he became Houston’s “imaginary bodyguard” due to the public perception of their characters’ relationship. “We had a moment, and I realized that the world had a higher idea of who we were, so I basically embraced it,” he said.

Kevin Costner reflects on delivering eulogy at Whitney Houston’s funeral

Costner also reflected on giving a eulogy for Houston at her funeral, two decades following their performance in “The Bodyguard.”

Houston died at the age of 48 in February 2012 after the singer was found dead in a hotel bathtub in Beverly Hills, California, just hours before music stars began to gather at the hotel for the annual Clive Davis pre-Grammy party. She died of an accidental drowning brought on by heart disease and longtime cocaine abuse, the Los Angeles coroner reported weeks later.

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While he was initially reluctant to speak at Houston’s memorial, Costner said he took his time to tribute his former co-star with his remarks at the ceremony, which totaled nearly 20 minutes.

“There were some people that really wanted to speak, and they’re kind of staring daggers at me. What was I going to say?” Costner said. “I started, and about 17 minutes later I was done.”

Contributing: Maria Puente, USA TODAY