In her first public comments about the relationships in decades, Soon-Yi Previn talks of the troubled relationship with her mother and describes how she fell in love with Allen – then Farrow’s boyfriend – in 1992.
The 47-year-old, in an article in the New York magazine, said she had decided to speak out because Dylan Farrow – who is an adopted daughter of Allen – has unfairly accused her husband of sexually abusing her when she was a child.
She said: “What’s happened to Woody is so upsetting, so unjust. (Mia) has taken advantage of the #MeToo movement and paraded Dylan as a victim.
“And a whole new generation is hearing about it when they shouldn’t.”
Previn criticised her adoptive mother’s parenting skills, describing her as not “maternal from the get-go” and a “total breakdown of your spirit”.
In the article, she said she has “a little learning difficulty”, and recalled Farrow suggesting she should be sent to “an insane asylum”.
Soon-Yi also claimed Farrow called her “stupid”, “moronic” and even held her by the feet “to get the blood to drain to my head” in order to help her learning.
The South Korean, who says she was born into poverty in Seoul and was living in an orphanage when Farrow adopted her, claims that when her prospective new parent hugged her “she didn’t ring true or sincere”.
She said she hated Allen at first, because he was in a relationship with her mother and “I didn’t understand why anyone could be with such a nasty, mean person. I thought he must be the same way.”
However the couple, who have been married for more than 20 years, became close and began a sexual relationship when she was at college.
Previn told the magazine: “I wasn’t the one who went after Woody – where would I get the nerve? He pursued me.
“That’s why the relationship has worked: I felt valued. It’s quite flattering for me. He’s usually a meek person, and he took a big leap.”
“From the first kiss I was a goner and loved him,” she added.
In 2014, Allen’s adoptive daughter Dylan Farrow wrote an op-ed for The New York Times in which she accused him of molesting her when she was seven. He was investigated but not charged and has always denied the accusations.
In separate statements responding to the article, Dylan Farrow and her brother Ronan said their mother is a good parent and described Previn’s comments as inaccurate and unfair.
Dylan Farrow reiterated her allegations against Allen on Twitter and accused the writer of the article, Daphne Merkin – a friend of Allen’s – of bias.
Ronan Farrow called his mother “a devoted mom” and said the magazine had done “something shameful”.
Allen faced a wave of criticism earlier this year, with several prominent actors vowing not to work with him again.
Associated Press attempted to contact Mia Farrow.