Ashley Graham has revealed she was sexually assaulted when she was a teenager.

The 29-year-old model has opened up about the horrific ordeal she was subject to on the set of a photo shoot aged just 17 years old, which saw her being led into a closet by one of the assistant photographers she was working with, who has remained unnamed, and asked to pleasure him.

Ashley managed to escape from the situation but it has haunted her ever since.

Speaking candidly about the incident to Glamour magazine, she said: ''There was an incident on set of a campaign job when I was 17 years old - I haven't told this story - and there was a photo assistant who was into me. He was like, 'Hey, come here,' and he led me into a closet. And I was like, 'What?' I thought he was going to show me something. And he pulled me in, and he pulled his penis out. And he was like, 'Grab it.' And I was like, 'No! That's disgusting.' I freaked out. And thank God I was closer to the door, and I just bolted out.''

And the fashion icon has admitted she has been forced to work with the culprit on other jobs, but remained tight-lipped about the previous situation in hope that he had reformed his behaviour.

She explained: ''I even knew a girl he dated. I didn't tell her because there was a voice in me that said, 'Maybe he's changed.'''

Although the horrible moment has stayed with her, Ashley insists the incident taught her the valuable lesson to never allow anyone to ''manipulate'' her again in the future.

The brunette beauty has also made a professional vow to herself to ''never'' pose entirely nude because she has set ''standards'' for herself.

Ashley - who is married to Justin Ervin - said: ''Ever since that incident, that I wasn't going to allow someone at work to manipulate what I wanted to do on set. Any image that you see out there is one that I wanted to take.

''My thing is: If it's vulgar, and it's, like, me grabbing my breasts and showing nipple, I'm not going to do it. When I said, 'I don't do nip and bush,' I didn't feel like I had to be specific as to what kind. So, you might even see more nipple coming up. But trust me: You will never see my vagina. Being a girl who waited until she was married to have sex with her husband but who is also a Sports Illustrated model is confusing for people. But I set standards for myself. I want my message to women to be, 'Do what is right for you.' ''