Katharine McPhee and Michael Morris
10/22/2013 at 02:00 PM EDT
star Katharine McPhee
has been photographed kissing a director for the canceled show, Michael Morris.
Both are married, though a source close to McPhee tells PEOPLE, "She and her husband are separated for over six months, since early this year. They haven't been living together."
McPhee, 29, is married to Nick Cokas
, who is also her manager. Morris, 47, and his wife, Welcome to the Family
actress Mary McCormack, have three young daughters together.
An agent for Morris and a rep for McCormack both declined to comment.
A source close to the couple, however, tells PEOPLE: "Mary adores her husband. If this is true, she would have been blindsided."
Adds the source: "She is the most devoted mother and wife."
Meanwhile, a rep for McPhee did not comment on her split from Cokas or what appears to be a new romance.
As for why the 2006 American Idol
runner-up may have called it quits with her husband, an on-set source tells PEOPLE, "I never noticed anything with Kat and the director on set at the time ... I do remember Kat's husband was always around and was very controlling."
According to TMZ, who first posted the kissing photo
, McPhee and Morris were holding hands and cuddling each other before the kiss was photographed.
With reporting by CHARLOTTE TRIGGS and ELIZABETH LEONARD