Eddie Cibrian. (Handout)

Actor Eddie Cibrian has launched a $1 million defamation lawsuit against magazine Life & Style over an article suggesting he's cheating on girlfriend LeAnn Rimes with a woman claiming to be an ex-mistress.

Cibrian threatened the legal action earlier this month and now he's following through, according to TMZ.com.

Aspiring actress Scheana Marie Jancan recently told the publication the American TV star is a serial cheat who will sleep with women behind Rimes' back.

Jancan warned Rimes, who quit her own marriage to date Cibrian, that the hunk will dump her after he has had his fun.

And, just last month, the publication ran a story suggesting Jancan and Cibrian were dating again - behind Rimes' back.

A statement from the star's representative says, "Unfortunately Life & Style Magazine has chosen to go out with a story filled with inaccuracies and deceitful lies, presumably to titillate sales, but clearly resulting in harm to Eddie Cibrian and others."

In the suit, lawyers claim the articles published by the magazine "falsely portray Eddie as being unfaithful to Ms. Rimes, as currently being in a romantic with Ms. Jancan, and as having abandoned his children."

Cibrian split from his wife Brandi Glanville earlier this year when he started dating country star Rimes.