Let's get together — the original "Parent Trap" turned 60 this year.
Decades before Lindsay Lohan did double duty in the 1998 remake, Hayley Mills played twins who scheme to reunite their estranged parents in the 1961 classic.
In an interview with TODAY, Mills reminisced about her dual role as sisters Susan and Sharon who trade places after meeting at summer camp.
The English actor said one of the biggest challenges was switching between both girls' accents; Susan grew up on her dad's California ranch, while Sharon is from Boston.
"A Californian accent was a little easier for me because I was surrounded by it," she said. "The Boston accent was somewhat elusive. And I think that shows in the film. But I was helped by the fact that the twins keep switching places. And they themselves got their accents muddled up, and I got my accent muddled up as well. So we were all in the same boat. But doing the split screen was was really fun, because I got to play each scene twice from two different people's point of view."
She added that she had a "wonderful actress" to play with, in double Susan Henning. "She was really really good about it," she said. "She never she never complained. And then she went on to become a dancer, and dated Elvis Presley. So she got one over me in the end."
As for tomboy Susan and proper Sharon, Mills said, "I think I enjoyed both of them equally."
One of Mills' favorite scenes is the camp dance at which Sharon cuts off the back of Susan's dress.
"They end up having a terrible fight, which was wonderful fun to do. Unfortunately, I forgot that I had to switch and play the other part in a moment."
"And I really enjoyed putting a cream pie in Susan Henning's face," she added. "And then of course, we had to switch roles. And I got the cream pie in my face. Instant karma."
In one of the movie's most memorable scenes, the sisters serenade their parents with "Let's Get Together," with Sharon at the piano and Susan playing a guitar.
"I didn't play well at all because I couldn't play the guitar," Mills recalled. "But, you know, I'm rather ashamed to say that actors got away with things in those days that certainly they wouldn't have got away with in a film today."
Mills said she loved working with Maureen O'Hara and Brian Keith, who played the twins' parents, and "learned how to behave on the set" from them.
"They were consummate professionals, both of them," she said. "And really, really sweet with me. If you work with really good actors, they make you better."
Mills has seen the 1998 version of "The Parent Trap" and praised Lohan's performance.
"I think she's excellent," she said. "It was a funny experience to watch it because it was so like the one I did. And yet not."
"And the split screen stuff was so good," she added. "You couldn't tell. I don't know how they did some things. I mean, the girls put their arms around each other, didn't they? Yes, it was amazing."
Mills said there are several reasons why the movie has remained beloved six decades later, including the story, the cast and David Swift's direction.
"But also, I think that it appealed to kids and adults, because for children, it was wonderful to see children taking charge of their lives, and sorting out the mess that their parents had made. And it came out actually, at a time when ... there was more divorce happening. So it struck a chord there. You know, it's one of those films where all the ingredients really came together really well."
Mills recently released a memoir, "Forever Young," and she hopes that fans "will see themselves in it."
"It's about growing up," she said. "It's about the struggle that we all have growing up, trying to find out who we are, as we leave childhood behind. And it was exactly the same for me. Only, you know, the circumstances of my life were so very, very different because of acting and those pressures, and the focus. And I guess, you know, the realization that I certainly had when I wrote it, that we spend our whole lives trying to come to terms and trying to understand our childhood and the effect that it had on us."