"But have I been told by a director to take off my shirt and show my boobs? Yes, I have. But did I do it? No, I did not," Lopez, now 48, told the magazine.
"When I did speak up, I was terrified. I remember my heart beating out of my chest, thinking, 'What did I do? This man is hiring me!' It was one of my first movies. But in my mind I knew the behaviour wasn't right," she added.
Lopez did not identify the man or the movie.
She credited her upbringing in New York City's tough Bronx borough in the 1970s for her refusal.
"I think ultimately the Bronx in me was like, 'Nah, we're not having it,'" Lopez said.
Sexual misconduct accusations against dozens of powerful men in Hollywood sparked the wider #MeToo social media movement, with hundreds of women coming forward in the past six months to share stories of assault and harassment.
Lopez, who began her career as a dancer and singer, is also a film and television actress and producer.
She followed a stint as a judge on "American Idol" with a lead role in the television police drama "Shades of Blue" and is the producer of shows including "World of Dance" and the upcoming romantic comedy movie "Second Act."