There has been much speculation surrounding the raunchy footage - which shows a blonde woman, now proved to be Tulisa, giving oral sex to an unidentified man - with fellow N-Dubz star and cousin Dappy apparently stating on Twitter that it was Contostavlos' ex-boyfriend, Fazer.
In the clip, Tulisa is seen with her now brunette hair scrapped back from her face, as she identifies that the man starring alongside her in the sex tape is in fact her former lover Justin Edwards a.k.a MC Ultra.
The 23-year old said: "I wanted to set the record straight on a certain tape circulating online, that consists of footage of me and my ex-boyfriend having an intimate moment,
"I have never been the type to sit down and keep my mouth shut, and to keep quiet about anything, especially when I've done nothing wrong whatsoever."
Holding up a picture of her ex to the camera, Tulisa continued: "This is the person, Justin Edwards aka Ultra, who is my ex-boyfriend, that has put it online, who is the other person on the tape.
"Justin is someone I was seeing from the age of 17 on and off for many years. By the time I was 19, we were together for a year and a half, I practically moved in with him and I loved him deeply. We talked about marriage, we talked about kids."
She went on to reveal she knew Edwards was threatening to release the sex tape online, explaining: "Six months ago, I got a call from a mutual friend saying that apparently he has footage of me, that he's been threatening to bring it out to ruin my career,
"I confronted him, he lied about it. And here we are today and the footage is now circulating online.
"As you can imagine, I am devastated, heartbroken. When you share an intimate moment with someone that you love and care about and trust, you never imagine that footage will be shared with the world."
Speaking of why she decided to come clean about the sex tape, the I Need You singer stated: "I don't feel that I should be the one to take heat or stick. This is something that he took upon himself to put online. He's now sitting in silence, saying it's not him on the tape, when it is.
"I have been deeply betrayed by him. This is something I've had to deal with, there's nothing I can do about it, but I do feel that I should share my side of the story."
The Female Boss concluded: "When you judge someone, it doesn't define the person you're judging, it defines you."
Winding up her video message, Tulisa thanked her followers for their support, adding: "Lots of love to my fans, I apologise to anyone that this has offended. I know for a fact it will not happen again."
Since Contostavlos' shock confession, Edwards has hit Twitter to write: "I believe in silence being a sign of Integrity but in this case I guess I'll have to speak up and Lay out the facts and let you guys decide."
He has previously denied all knowledge of the sex tape, tweeting on 19th March: "I didn't wanna say anything on the subject but I see peoples imagination running away.. it's nothing to do with me.#backtowork
"Keepin my twitter quiet outta respect for a certain someone no other reason than that."
Tulisa has since obtained a gagging order from the High Court, preventing anyone from using, publishing, communicating or disclosing to any other person, all or any part of the raunchy film.
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