"I can say that he will be coming to Sweden soon, but I can't say when," Ullman PR chief executive Harald Ullman told AFP.
"We will be helping him handle the media pressure," he explained, saying his company would begin its work while Assange was still in Britain.
The founder of whistleblower website WikiLeaks lost a bitter legal battle last week when London's High Court ruled he could be extradited from Britain to Sweden, but he still has until November 16th to appeal the ruling to the Supreme Court.
Ullman would not say if the preparations he had been hired to handle meant the 40-year-old Australian had decided to drop the final appeal.
Assange's Swedish lawyer Björn Hurtig meanwhile told AFP he had not been informed that his client had hired a PR company.
"I haven't heard anything about that at all," he said.
Swedish prosecutors want to question Assange on suspicion of two counts of sexual molestation and an accusation of rape made by two Swedish women in August 2010.