EXCLUSIVE: Bob Newhart Reflects on Mary Tyler Moore's 'Groundbreaking' Television Legacy

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Bob Newhart is opening up about his memories of the late Mary Tyler Moore and how the pioneering actress changed the television landscape forever.

"She was a great comedic actress," the sitcom icon shared while sitting down with ET's Nischelle Turner at his home in Los Angeles on Wednesday, where he reflected on the many ways Moore's beloved 1970s sitcom, The Mary Tyler Moore Show, was unlike anything audiences had seen before.

"I remember there was one scene, it was Nanette Fabray, [who played] Mary's mother, and my father-in-law Bill [Quinn] played her father," Newhart recounted. "Nanette turned around and said to the two of them, 'Don't forget your pill.' And Bill said, ‘I won't,' and Mary said, 'I won't' and it was like, 'Whoa! Why would she be taking a pill?' It was really groundbreaking."

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According to the 87-year-old screen legend, who knew Moore for decades, her talent as a comedic star came from knowing her own voice and understanding how to make scripts play to her strengths as an actress.

"The thing I think that a performer brings to a role is they know themselves. In other words, they could write a great line but you have to say, 'That's not me, that's me,'" the Golden Globe winner explained. "That's a thing, and Mary had that ability to say: 'Yeah that's right for me.'”

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Newhart also opened up about the last time he spoke with Moore, which happened a few years ago when trade rumors circulated that Newhart would be appearing in a project with Moore's longtime friend and former co-star Betty White. He told ET he got a call from Moore asking to be a part of the rumored project.

"I said, 'Well they kind of screwed it up. I may do something, she may do something, but we're not doing anything [together],'" Newhart said. "She said, 'If you ever do something together I want to be part of it.' Because she loved to work, she just loved to work."

When it comes to what he'll miss most about the venerated actress, Newhart fondly recalled her smile, sharing, "What a great smile." When it comes to what he'll remember the most, the answer was clear: her "great delivery of great lines."

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In the end, Newhart had a message for Moore, which he said was "probably what millions are saying right now: Thank you."

The pioneering actress, who won six Emmy Awards and three Golden Globes over the course of her illustrious 60-year career, died on Wednesday at age 80, surrounded by her close friends and husband of 33 years, Dr. S. Robert Levine.

Moore's death was caused by cardiopulmonary arrest after she had contracted pneumonia. For more on the celebrated star's life and legacy, watch the video below.