LeAnn Rimes is allegedly "obsessed" with Brandi Glanville.
The 30-year-old How Do I Live singer - who has been married to Brandi's ex-husband Eddie Cibrian (39) since April 2011 - has been accused of stalking the Real Housewives of Beverly Hills star and attempting to copy her every move.
A source told Star magazine: "It's out of control, the way LeAnn stalks Brandi. Even LeAnn's friends think it's weird, but she can't seem to help herself.
"If Brandi tweets a picture of herself in a bikini, LeAnn does the same thing. If Brandi talks about becoming a dermatologist, LeAnn suddenly starts talking about it on Twitter ... it's really strange!"
According to friends close to the 40-year-old reality TV star - who shares two sons Mason (nine) and Jake (five) with Eddie - Glanville is well aware that LeAnn is emulating her.
Her long-time pal Jennifer Gimenez said: "She copies everything that Brandi does. She even exchanged her black Range Rover for a white one because that's what Brandi drives! If Brandi gets a new bag or shoes, within a week you will see LeAnn with the exact same thing."
Another insider said: "LeAnn used Brandi's boob doctor, Garth Fisher; her dentist, Dr Duane McKay; her hairstylist, Kim Vo; her dermatologist, Dr Harold Lancer; and the same Botox guy at Dr Applebaum's!
"It is disturbing – she finds out who Brandi uses, then goes out of her way to book an appointment with them herself.
"Ever since LeAnn got Eddie, all she can think about is how to keep him, and it's making her act like a lunatic. She has it in her head that if she looks and acts just like Brandi, Eddie won't ever leave her. Which obviously makes no sense, because Eddie cheated on Brandi with LeAnn!"
LeAnn recently debuted her new song Broken and admitted it is about her 2009 affair with Eddie, after they met on the set of their TV movie Northern Lights when was married to Dean Sheremet and he was wed to Brandi.