Legendary American actress and singer Doris Day has died at her California home at the age of 97, her foundation has said.

The Doris Day Animal Foundation confirmed the legendary Hollywood star died early on Monday surrounded by her close friends at her home in Carmel Valley.

Day, who starred as Calamity Jane in the 1953 film, "had been in excellent physical health for her age, until recently contracting a serious case of pneumonia", according to her foundation.

She was known as a honey-voiced singer and actress whose film dramas, musicals and comedies made her a top star in the 1950s and 60s and among the most popular screen actresses in history.

Day's lilting voice, wholesome blond beauty and ultra-bright smile brought her a string of hits, first on records, and then later in Hollywood.

She turned 97 on April 3, and Day told the Hollywood Reporter she celebrated all week with "dear old friends out of town" and enjoyed "quiet dinners".