The Sound Of Music actress who played Liesl Von Trapp, Charmian Carr, dies age 73.

The actress who played Liesl Von Trapp in one of the greatest musicals of all time, The Sound of Music, has died.

Charmian Carr passed away in California from complications due to a rare form of dementia at age 73.

The actress was known for playing the oldest of the Von Trapp children and singing I Am Sixteen Going on Seventeen in the 1965 film, which also starred Julie Andrews and Christopher Plummer.

Her death was confirmed in a statement on the actress' official website.

"My name is Steve Hughes, and my Company has been managing Charmian Carr's website for many, many years. Me and my family are so sad to have to post this message and will miss her dearly," the statement read.

"She was such a nice, cheerful person. We always LOVED, The Sound of Music."