Out of all her six Sound of Music siblings, Heather was closest with Angela Cartwright, who played her younger sister Brigitta. Only two years apart in real life, neither of the girls had many friends, so they bonded quickly. They used to have slumber parties, play the guitar, sing, and fantasize about meeting the Beatles. They are still friends to this day.
Heather Menzies: (about child stardom) No one can understand how difficult it can be, unless you've been through it. It sounds so trivial and trite, but the reality is, it affects you. As a young person, you have to find your way through it. It was the worst for me when I entered adulthood. Even though I was doing Broadway shows and other roles, it was a constant battle to get past 'Oh, you're Louisa!' People would look me up and down and frown. 'You don't look like her anymore.' I'd see their disappointment and feel frustrated. I was letting people down because I wasn't thirteen years old anymore. It was as if they wished I'd been freeze-dried as Captain von Trapp's daughter. I rebelled for a while. I went out of my way to be totally different.
Heather Menzies: (about filming "The Sound of Music") I'd always been a wallflower. Shy. I didn't tell anybody I was doing this movie. I went away, and they all thought I got pregnant or something. When I came back, I didn't tell anyone where I'd been. All of a sudden, the movie came out, and all these people who never knew me, or cared to know me, were suddenly approaching me saying, 'Oh, Heather, I've always thought you were so wonderful, and you're my best friend.' It was so transparent.