The Harry Potter star, 23, began dating Adamowicz after meeting him at Oxford in 2011 and though there were recent rumors the couple was close to getting engaged, a report from British newspaper The Mirror claims otherwise.
"Emma and Will separated last summer and are no longer in touch," Watson's rep reportedly told the publication.
The announcement comes days after 23-year-old Adamowicz was pictured close to a powdery substance, a $100 bill and a New York City MetroCard. Adamowicz denied allegations that the substance in the image was a drug.
"The picture is not compromising," he said of the image. "It is not what you think. They are not packages. They are not drugs. They are just bits of scrap paper. I don't take any drugs."
Watson and Adamowicz were last seen together in London in November.