Charmian Carr, who played Liesl Von Trapp in The Sound of Music, has died after complications from a rare form of dementia. She passed away in Los Angeles this past Saturday. She was 73.

In the 1965 film version of the musical The Sound of Music the actress portrayed the oldest von Trapp daughter and famously performed the song “Sixteen Going on Seventeen.”

“It’s always sad when a member of the family passes away — and in the case of the ‘family’ of the movie ‘The Sound of Music,’ it’s especially sad when it is the first of the group to go,” said Ted Chapin, president of the Rodgers & Hammerstein organization, in a statement. “Charmian Carr played the oldest von Trapp child, and in some ways she maintained that role in real life — guiding, cheering, supporting and generally being there for the rest of her ‘sisters’ and ‘brothers.'”

The Sound of Music was Carr’s most major Hollywood role, but she also starred with Anthony Perkins in the television musical Evening Primrose.

The actress wrote a pair of books about her experience with The Sound of Music titled “Forever Liesl” and “Letters to Liesl.” Carr fully accepted her audience’s obsession with the film, and frequently made appearances at fan events celebrating the film. This included sing-a-long performances at the Hollywood Bowl.

Carr later went on to become an interior designers in Southern California. Her clients included Michaeal Jackson and Sound of Music screenwriters Ernest Lehman.

Carr was born in Chicago in 1942 where her morther was an actress and her father an orchestra leader. Carr is survived by four siblings, two children and four grandchildren. She was also survived by the six other actors that were cast as the von Trapp children.