The singer, 53, claimed to have had a brief relationship with the actress, 37, in his autobiography When It Fell Apart, released last month, after the pair met backstage at one of his shows.
“I was a bald binge drinker and Natalie Portman was a beautiful movie star,” he wrote.
“But here she was in my dressing room, flirting with me. I was 33 and she was 20 but this was her world.”
Moby, real name Richard Melville Hall, said that he then “tried to be Natalie’s boyfriend” but things “hadn’t worked out,” and claimed that he was relieved when she eventually broke things off.
“I thought that I was going to have to tell her that my panic was too egregious for me to be in a real relationship, but one night on the phone she informed me that she’d met somebody else,” he wrote.
“I was relieved that I’d never have to tell her how damaged I was.”
Speaking to Harper’s Bazaar UK, Portman denied a romantic involvement with the singer and said that she was actually 18 when she met him.
“I was surprised to hear that he characterised the very short time that I knew him as dating because my recollection is a much older man being creepy with me when I had just graduated high school,” she told the publication.
“He said I was 20; I definitely wasn’t. I was a teenager. I had just turned 18.”
She described Moby’s account as “very disturbing” and filled with “factual errors and inventions,” adding: “I would have liked him or his publisher to reach out to fact check.”
“I was a fan and went to one of his shows when I had just graduated,” she continued. “We only hung out a handful of times before I realised that this was an older man who was interested in me in a way that felt inappropriate.”
Standard Online has contacted a representative for the musician for further comment.
The full interview can be found on Harper’s Bazaar UK online.