LOS ANGELES (AP) — Charmian Carr, the actress best known for sweetly portraying the eldest von Trapp daughter in Rodgers & Hammerstein’s “The Sound of Music,” has died. She was 73.

Carr died Saturday of complications from a rare form of dementia in Los Angeles, Carr’s spokesman, Harlan Boll, said.

At age 21, the actress portrayed Liesl von Trapp in the 1965 film version of the musical “The Sound of Music.”

She famously performed the song “Sixteen Going on Seventeen.”