EXCLUSIVE: Debbie Turner is mourning the loss of her "Sound of Music" co-star Christopher Plummer.

The award-winning actor, who played Captain von Trapp in the 1965 musical, passed away on Friday at age 91. His wife Elaine Taylor was by his side.

"He was always in character," the former child star, who played Marta von Trapp, told Fox News on Friday. "He would give you a look even if you smiled. So we sort of tiptoed around him. We were just cautious because he gave off that air of authority towards us, but that was so we could react on camera towards him like how we were supposed to. That’s why he was always in character."

Plummer, who enjoyed a decades-long career in Hollywood, played varied roles. At 82, he became the oldest Academy Award acting winner in history. 

CHRISTOPHER PLUMMER, 'SOUND OF MUSIC' STAR AND HOLLYWOOD LEGEND, DEAD AT 91

Debbie Turner (being held by Christopher Plummer) starred in 'The Sound of Music' alongside the late actor.

Debbie Turner (being held by Christopher Plummer) starred in 'The Sound of Music' alongside the late actor. (Courtesy of Debbie Turner)

But it was opposite Julie Andrews as von Trapp that made him a star. He depicted an Austrian captain who must flee the country with his folk-singing family to escape service in the Nazi navy.

Later in life, Plummer experienced a film renaissance, which began with his performance as Mike Wallace in 1999’s "The Insider." In 2012, he won a supporting actor Oscar for his role in "Beginners" as Hal Fields, a museum director who becomes openly gay after his wife of 44 years passes away.

Then in 2017, he replaced Kevin Spacey as J. Paul Getty in "All the Money in the World" just six weeks before the film was supposed to hit theaters. He received a supporting Oscar nomination for the role.

Turner described how she and the rest of the "Sound of Music" cast reunited in 2010, the first time in 45 years for an Oprah Winfrey special. Before the televised event, she gave Plummer a special gift.

CHRISTOPHER PLUMMER'S MOST MEMORABLE ROLES FROM 'THE SOUND OF MUSIC' TO 'KNIVES OUT'

Debbie Turner (right) reunited with her on-screen father in 2010 for a special on Oprah Winfrey's talk show.

Debbie Turner (right) reunited with her on-screen father in 2010 for a special on Oprah Winfrey's talk show. (Photo courtesy of Debbie Turner)

"After we finished filming the movie, Julie Andrews had thrown a wrap party for us," said Turner. "It was a swimming party at her house and he was there. I remember my mom was so nervous about taking this photo because she thought, ‘Oh my God, it’s Christopher Plummer.’ 

"But I didn’t care," she continued. "I just saw him as my daddy in the movie. It was a very sweet picture. Well, before the Oprah special, we had dinner in Chicago and I gave him a copy of that picture. He was like, ‘Wow, I was quite a catch back then, wasn’t I?'"

Today, Turner is a successful upscale floral designer. The former actress also designs scarves and facial masks using fabrics similar to the ones that the von Trapp children used. Still, she will always remember her time on set with Plummer.

"It was an honor and privilege to have known him, to have worked him with, and to have played his daughter," Turner added.

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Actor Christopher Plummer won the best supporting actor award for 'Beginners' in 2012.

Actor Christopher Plummer won the best supporting actor award for 'Beginners' in 2012. (Getty Images)

Plummer’s manager, Lou Pitt, also confirmed his death in a statement sent to Fox News.

"Chris was an extraordinary man who deeply loved and respected his profession with great old fashion manners, self-deprecating humor and the music of words. He was a National Treasure who deeply relished his Canadian roots," Pitt said. "Through his art and humanity, he touched all of our hearts and his legendary life will endure for all generations to come. He will forever be with us."

Fox News’ Melissa Roberto and The Associated Press contributed to this report