Heather Menzies-Urich, who played one of the von Trapp sisters in The Sound of Music, died Sunday at age 68.

Menzies-Urich, the Toronto-born widow of actor Robert Urich, was recently diagnosed with brain cancer, her son Ryan told Variety. The estate of Rodgers and Hammerstein, which produced the Oscar-winning 1965 musical, also confirmed the death.

Menzies-Urich played Louisa von Trapp in the film, released when she was 15. She got her acting start in The Farmer's Daughter, a 1964 TV adaptation of another film, and went on to appear in several movies and TV series, including Logan's Run and Vega$, which starred her second husband Urich, whom she married in 1975. He died in 2002, also of cancer, and she formed a foundation in his name to sponsor cancer research.

“She was an actress, a ballerina and loved living her life to the fullest,” Ryan Urich told Variety. “She was not in any pain but, nearly four weeks after her diagnosis of terminal brain cancer, she had enough and took her last breath on this earth at 7:22 p.m.”

Kym Karath, who played sister Gretl in The Sound of Music, tweeted her condolences:

"I am filled with infinite sadness tonight. My precious friend and SOM sister Heather Menzies passed away this evening. Devastated."

And Karath and other surviving actors from the film sent a statement Tuesday mourning Menzies:

"With great sadness we bid our beloved sister, Heather Menzies, goodbye. Just over a year ago, the film vonTrapp children gathered to say farewell to our oldest sister Charmian Carr. It is unbearably painful that in such a short time we have now lost another member of our family. Heather’s warmth, generosity and total lack of pretension has been a shining example to all of us for over 50 years. We were so blessed to have met her on The Sound of Music, and that blessing continued every day until Christmas Eve, 2017. We send our love, admiration and deepest sympathy to her family. Our Louisa, Heather, will never leave us and we will never leave each other." —Nicholas Hammond, Duane Chase, Angela Cartwright, Debbie Turner, Kym Karath