Thing you know everything there is to know about the Von Trapps? Think again!

By Lynette Rice
Updated October 05, 2016 06:19 PM
Credit: Everett

The hills are alive! As The Sound of Music turns 50, Julie Andrews and Christopher Plummer share their memories of making the classic movie. Subscribe now for instant access behind-the-scenes, only in PEOPLE.

It’s been 50 years since The Sound of Music premiered in movie theaters – but even fans who’ve seen it again and again (you know who you are!) don’t know everything about the Oscar-winning musical.

In the magazine’s new issue, PEOPLE asked stars Julie Andrews (Maria) and Christopher Plummer (Captain von Trapp) to spill a few more secrets as the anniversary celebrations kick off.

There’s a new five-disc Blu-ray/DVD collection a screening of the film at the TCM Classic Film Festival in Hollywood later this month, screenings at 500 movie theaters nationwide in April and an ABC special with Diane Sawyer on Wednesday night. There’s also a slew of new books about the movie, including The Sound of Music Companion (with a foreword by Andrews) and The Sound of Music Story (by Tom Santopietro).

Here are five things you may not know about the classic film:

‘My Favorite Things’ was the first scene Andrews shot with the children
“All of the kids were in the bedroom and the thunderstorm was going on,” recalls Andrews, 79. “I wanted to make them feel as much at home as possible, so I did a lot of clowning whenever it came time for one of their closeups to make them crack up or smile. They fell into it so easily.”

Plummer had a few too many crisp apple strudels
“The Austrians know how to make you fat in two seconds,” he says. “Of course, when I got back to shooting, director Bob Wise looked at me and said, ‘Goddammit, you look like a whale. We gotta re-do your whole costume.’ So they did. In those days we didn’t care how much we gained. Isn’t that funny? We care so much now. I didn’t give a damn. I just had a good time.”

Andrews can – and did – sing ‘Supercalifragilistic’ backward
She had just played Mary Poppins, and the Sound of Music child stars asked her sing it – forward and backward. “They loved it,” she says. “And it did help us bond.”

There was on-set romance
The Baroness, a.k.a. Eleanor Parker, didn’t end up with the captain, but she did find love in Salzburg. “Eleanor had great fun because she fell in love with the cameraman and they had a marvelous time together,” remembers Plummer, 85. “He was an awfully nice guy and she deserved a nice guy. She was the most delicious woman, and, my god, what a beauty, so I loved them both and they were such lovebirds always holding hands everywhere. I think their story is much more romantic than The Sound of Music.”

Fans’ reactions can still surprise Andrews
“I did meet a little 13-year-old boy the other day who probably hadn’t been exposed to it much, and if he had seen me he wasn’t expecting that it would be me, 50 years later and that he was meeting me,” says Andrews. “He looked very bewildered and he said, ‘So, you are Julie Andrews?’ and I said, ‘Yes! Still!’ I couldn’t help it because it was like, ‘Oh, heavens!’ It struck me as very sweet and funny. It struck me as darling.”

For much more about The Sound of Music, including rare behind-the-scenes photos, pick up the latest issue of PEOPLE, on newsstands Friday

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