The New York Daily News reported the mother of two girls had been sick for about a decade and died last Thursday. The cause of her death was not released to the public and Previn's live-in boyfriend, Robert Garcia, declined to comment on his loss to the Daily News.
A wake was held for Previn Monday, the newspaper said.
Farrow and her former husband, musician Andre Previn, adopted Lark in 1973. She was the first of many children Farrow would adopt over the years.