"They had four takes at the lake and they're falling in over and over," Diane said of the film's famous lake scene. "Getting dried off then getting wet down when they need to be and then she's told early on that the smallest child doesn't swim. She has to fall in such a way that she can catch her but instead she falls in the opposite way and we have footage because the families, the parents of the children, were taking home movies."
Another secret? The stream that Julie Andrews jumps in wasn't even there!
"They brought it in," Diane said. "The birch trees -- they'd bring them in and take them away."
While the famous hill that Julie twirls on is still there, it's hard to get to. The land is privately owned and can't be found on a map, but Diane and her crew gained access. Julie told Diane how she made it up the hill.
"We actually went up the mountain in big open carts pulled by oxen," Julie said. "I would sit on top of all the camera equipment they would hoist me up."
And what about Julie's real favorite things?
"My kids," Julie told Diane. "Of course they come first."
Gardening and martinis were also on the list.
Watch the video to see Julie visit the real von Trapp home for the first time!