Sienna Miller involved with married man Balthazar Getty?

Sienna Miller is implicated in the end of Brothers & Sisters star Balthazar Getty’s marriage, according to a new report.

The News of the World is reporting that Sienna has spent several nights this week with Balthazar, after being introduced by his television show co-star, and her Edge of Love co-star and on-off fling, Matthew Rhys.

A source told the newspaper: “Sienna got to know Balthazar through Matthew and they hit it off. In the past three months they have grown incredibly close.

“Getty even secretly flew to London and Prague to be with Sienna to get to know her even better. And she’s spent this week in a Hollywood house with him.”

The source explained the pair have attempted to keep their romance a secret: “They went to great pains to find a place where they thought nobody would find them. They daren’t go out together, so they spend most of their time inside. When they do leave, they go separately.”

But it’s not been kept a secret from everyone: “[His wife] Rosetta found out about them and has now fled to Italy. She can’t believe her husband could do this to her. The whole family now know and everybody is devastated.

“She is furious with Sienna, but even madder with her husband. She can’t believe he could throw away all they shared over some young blonde.

“Even though Balthazar loves his wife and [their four] children, he cannot stay away from her.”

Sienna split from boyfriend of a year Rhys Ifans at the start of this month.