US Heiress, Actress Dina Merrill Dead at 93

American heiress Dina Merrill, the Hollywood socialite who became a leading lady, has died aged 93.

Merrill, raised in part on the Mar-a-Lago estate in Palm Beach, Florida, now owned by President Donald Trump, died in New York on Monday after a battle with dementia, according to US media reports quoting family sources.

Merrill appeared in more than 20 films and dozens of TV series after making her big screen debut in "Desk Set," a 1957 romantic comedy starring Katharine Hepburn and Spencer Tracy.

Her co-stars during a career that lasted well into the 2000s included Robert Mitchum, Cary Grant, Tony Curtis and Elizabeth Taylor.

Merrill's mother Marjorie Merriweather Post, an heiress to the Post cereal fortune, was estimated to be worth $250 million when she died in 1973. 

The actress had two daughters and two sons, during marriages to wartime fighter pilot and Colgate heir Stanley Rumbough Jr. and actor Cliff Robertson.

In 1989 she married Ted Hartley, another former pilot, and the couple bought down-at-heel studio RKO Pictures, remaking the 1949 movie "Mighty Joe Young" in 1998.

"I had the pleasure to work with the beautiful Dina Merrill in 'The Courtship of Eddie's Father'. So sorry to hear of her passing," director Ron Howard, who acted opposite her in the 1963 romantic comedy, said in a Facebook post.