Raquel Welch's cause of death has been revealed as a heart attack following a secret Alzheimer's battle

TMZ which obtained the document, said: "The actress had not publicly revealed she was battling Alzheimer's."

The death certificate says she passed away at 2.25am, and revealed the star was cremated.

Raquel's long Hollywood career was also noted on the certificate, with a doctor saying on the document she spent 60 years as an actress in the entertainment industry.

She was said to have suffered heart failure while at home in southern California.

Her long-term business manager Steve Sauer confirmed the news of her death in a press release in February, saying: "Her career spanned over

50 years starring in over 30 films and 50 television series and appearances.

"The Golden Globe winner, in more recent years, was involved in a very successful line of wigs.

"Raquel leaves behind her two children, son Damon Welch and daughter Tahnee Welch."

After her break-out roles in 'Fantastic Voyage' and 1966's 'One Million Years B.C.' in 1966, Raquel - born Jo-Raquel Tajeda - appeared in a huge range of films and TV series, earning a Golden Globe for her role as Constance de Bonacieux in the 1974 remake of 'The Three Musketeers'.

The actress started out studying ballet, but gave up aged 10 years when her instructor told her she did not have the right body type for professional dance companies.

She won beauty pageants as a teen and was named Maid of California, before working as a weather forecaster for a San Diego TV station, and had jobs as a cocktail waitress before moving to Los Angeles in 1963 to chase her dream of becoming a movie star.

After shooting to fame, she was named the Most Desired Woman of the 1970s by Playboy, but refused to pose naked for the magazine or any of her films.

She said: "I've definitely used my body and sex appeal to advantage in my work, but always within limits.

"I reserve some things for my private life, and they are not for sale."

Four-times married Raquel was wed to James Welch from 1959 to 1964, Patrick Curtis from 1967 to 1972, Andre Weinfeld from 1980 to 1990, and Richard Palmer from 1999 to 2004.

She had her two children with her first husband and in 1994 received a star on the Hollywood Walk of Fame.