A source close to the actor tells the CNN split took place earlier this year.
"Michelle and Phil were separated at the beginning of the year. It was a possible waste and they remained friends," said the source of CNN.
A representative of Williams refused to comment. CNN has also reached Elverum's representatives and is awaiting an answer.
Williams described his relationship with Elverum to Vanity Fair as "very sacred and very special."
The 38-year-old actress, known for her roles on the television series "Dawson & # 39; Creek" and the movie "Brokeback Mountain" was earlier in a three-year relationship with actor Heath Ledger. They had a daughter before Ledger died of an unintentional overdose of prescription drugs in 2008.
Elverum, the frontman of the band Microphones and Mount Eerie, lost his wife Geneviève Castrée to pancreatic cancer in 201