The singer has said she was drugged and raped after being held captive by an attacker.
In a post on her verified Instagram account, the Welsh performer added that her "recovery took time".
It is not clear where or when the ordeal took place.
The 35-year-old singer, whose full name is Aimee Anne Duffy, had a UK number one album with her release Rockferry in 2008.
The following year she won three BRIT Awards (British Breakthrough, Best Female Solo and Best British Album) and a Grammy (Best Pop Vocal Album).
She wrote in her post on Tuesday: "You can only imagine the amount of times I thought about writing this. The way I would write it, how I would feel thereafter.
"Well, not entirely sure why now is the right time, and what it is that feels exciting and liberating for me to talk.
"I cannot explain it. Many of you wonder what happened to me, where did I disappear to and why.
"A journalist contacted me, he found a way to reach me and I told him everything this past summer.
"He was kind and it felt so amazing to finally speak.
"The truth is, and please trust me I am OK and safe now, I was raped and drugged and held captive over some days. Of course I survived. The recovery took time."
The singer's best known singles include Warwick Avenue, Mercy and Stepping Stone.
Her statement was the only post on her Instagram page on Tuesday night.
It continued: "There's no light way to say it. But I can tell you in the last decade, the thousands and thousands of days I committed to wanting to feel the sunshine in my heart again, the sun does now shine.
"You wonder why I did not choose to use my voice to express my pain? I did not want to show the world the sadness in my eyes.
"I asked myself, how can I sing from the heart if it is broken? And slowly it unbroke. In the following weeks I will be posting a spoken interview.
"If you have any questions I would like to answer them, in the spoken interview, if I can.
"I have a sacred love and sincere appreciation for your kindness over the years. You have been friends. I want to thank you for that x.
The singer's second album Endlessly was released in 2010 and was judged to be a commercial failure.
Duffy is then reported to have retreated from the limelight after struggling with the demands of fame.
Three years later she is said to have made a live appearance at New York's Beacon Theatre, where she performed a version of the French singer Edith Piaf's song Hymn To Love.
Duffy's former mentor Bernard Butler reportedly expressed his sympathy for the way her career had faltered in an interview in 2014.
He said: "She went off the rails and it all went pear-shaped for her. And maybe she brought all those problems on herself."
Duffy is reported to have remained out of the limelight until 2015 when she played the late American singer Timi Yuro in the film Legend about the Kray twins.
In a Instagram post in October 2017, which appears to have since been deleted, Duffy seemed to hint she was releasing new music.
She wrote: "I will not be online now until the other side of the year. Other news is - I will see you, with something you, at some point soon.
Duffy also hinted she might be making a return to music in December last year when she posted a photo of herself with the caption "2020" on Facebook.