Firth's wife of 20 years, Livia Giuggioli, confirmed that she had an affair with the man she now says is stalking her.
Giuggioli, who is a film producer, accused Italian journalist Marco Brancaccia of harassing her after their brief romance. According to British newspaper The Times, Brancaccia has denied those claims, saying Giuggioli merely wants to cover up their relationship of a few years ago.
Per a statement sent to the Times, Firth and Giuggioli were separated during the time of the affair: "Livia briefly became involved with former friend Mr. Brancaccia. The Firths have since reunited. Subsequently, Mr. Brancaccia carried out a frightening campaign of harassment over several months, much of which is documented. For obvious reasons, the Firths have never had any desire to make this matter public."
The statement attributes the news becoming public to a "leaked court document."
Firth's reps did not respond to People for comment.
Per The Daily Beast, Firth became an Italian citizen last year. The couple lives in Umbria most of the year with their two teenage sons.