On Wednesday, Delevingne posted a long note as a caption to a photo on Instagram.
"Don't be ashamed of your story it will inspire others," the photo read.
In her caption, Delevingne recounts a story from early in her career where she alleges she "received a call from Harvey Weinstein asking if I had slept with any of the women I was seen out with in the media."
"It was a very odd and uncomfortable call," said the actress, who has described herself as sexually fluid
. "I answered none of his questions and hurried off the phone but before I hung up, he said to me that If I was gay or decided to be with a woman especially in public that I'd never get the role of a straight woman or make it as an actress in Hollywood."
A year or two later, Delevingne wrote, she took a meeting with Weinstein and a director in a hotel lobby.
Things took a turn, according to Delevingne's account, after the director left the meeting.
"As soon as we were alone he began to brag about all the actresses he had slept with and how he had made their careers and spoke about other inappropriate things of a sexual nature," Delevingne wrote. "He then invited me to his room."
The actress said she declined, asked his assistant if her car was ready outside, was told it would be awhile and that she should go to Weinstein's room.
Despite feeling "powerless and scared," Delevingne said she decided to go and act as if nothing was wrong.
Once there, Delevingne alleges there was another woman in the room whom Weinstein asked her to kiss.
"I swiftly got up and asked him if he knew that I could sing," she wrote. "And I began to sing....i thought it would make the situation better....more professional....like an audition....i was so nervous."
Delevingne then said she got out of the room, allegedly after Weinstein tried to kiss her on the lips, and ended up with the role.
She said she kept silent because "she didn't want to hurt his family."
"I felt guilty as if I did something wrong," she wrote. "I was also terrified that this sort of thing had happened to so many women I know but no one had said anything because of fear."
The actress's representatives have not responded to CNN's request for comment.
Delevingne appeared in the Weinstein produced film "Tulip Fever," which was shot in 2014 and just released in September.
In August, Weinstein wrote an opinion piece for Deadline
in which he defended the film and talked about the audience response at a screening.
"No, they weren't telling me that it's 'Citizen Kane' or 'Shakespeare In Love,' but they loved the performances, the cinematography, the costumes, the twists and turns, and enjoyed it for the film it is," Weinstein wrote. "I'm sure that the critics will have their fun with it, but I'm proud of this movie, as is the rest of the team behind it."
When asked about rape and sexual misconduct allegations by other women on Tuesday, a representative for Weinstein released a statement to CNN.
"Any allegations of non-consensual sex are unequivocally denied by Mr. Weinstein. Mr. Weinstein has further confirmed that there were never any acts of retaliation against any women for refusing his advances," the statement read in part.
The spokeswoman added that Weinstein was seeking treatment and would not be available for further comment.