The 28-year-old actress was recently photographed looking much thinner than usual, and despite her insistence that she is healthy friends are worried that she is taking her pre-wedding diet too far.
A source told Now magazine, 'LeAnn's set herself a target and she won't be deterred. Everyone's trying to tell her she doesn't need to lose more weight but she won't listen. She's reduced her portion sizes and has even been skipping meals.
'She used to love her food but now she's obsessed with counting calories and is working out way more than she used to.'
Rimes and Cibrian had an affair with each other behind their then-spouses' backs and got engaged last December.