This post contains mentions of sexual assault and may be triggering to some readers.
"[I] was at his apartment because I wasn’t working that day," Farrow explained in HBO's new documentary series, Allen v. Farrow.
"[There was a] stack of Polaroid pictures, of pornographic pictures of a woman, a girl. And I picked them up, and I realised all of them were of Soon-Yi. It was my own child," she continued.
Watch the trailer for Allen v. Farrow below. Post continues after video.
"They wouldn’t put them in Playboy," Farrow said of the photos. "They were Hustler pictures. Really, really raunchy pictures."
At the time, Allen was 56 and Previn was 21.
Previn, who was adopted by Farrow and her former husband (composer André Previn) as a child, was in her first year of college, while Allen had been in a relationship with Farrow for more than a decade.
When Allen and Previn's relationship later surfaced publicly, Allen admitted that he had no moral qualms with their relationship.
"I didn't feel that just because she was Mia's daughter, there was any great moral dilemma. It was a fact, but not one with any great import. It wasn't like she was my daughter," he told Time Magazine in an August 1992 interview.
"I am not Soon-Yi's father or stepfather. I've never even lived with Mia. I never had any family dinners over there. I was not a father to her adopted kids in any sense of the word."
Previn agreed, later telling Vulture in 2018: "We didn’t think of him as a father. He didn’t even have clothing at our house, not even a toothbrush."
In the controversial exclusive interview with the publication, Previn shared she was "madly in love" with Allen.