The pair have split due to the 23-year-old actress' hectic film schedule and they are no longer in contact with each other, reported Dailt Mirror.
The shock separation comes despite rumours of an impending engagement between Watson and the millionaire's son.
Watson, best known for her role as Hermoine Granger in the 'Harry Potter' films - and Adamowicz met as students at Oxford in 2011.
They were last spotted together in November at the Shepherd's Bush Empire in west London, watching acoustic folk rock trio The Staves.
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The Oxford graduate is seen with white powder spread across a table in front of him.
But, responding to the suggestion that the picture is compromising, Adamowicz denied the packets in the picture contained drugs.
A short time later the account which featured the picture was deleted.
The former 'Harry Potter' actress is starring in upcoming blockbuster 'Noah' where she plays the titular character's adopted daughter Ila alongside Russell Crowe as Noah and Jennifer Connelly as his wife.