Naya Rivera didn't think much of Kim Kardashian's naked butt shots! Credit: David M. Benett/Getty Images, JB Lacroix/WireImage via Getty

Celebrity feud alert! Seems Naya Rivera doesn't think much of Kim Kardashian's decision to pose buck naked on the cover of Paper magazine's winter 2014 issue — and she's not shy about making her opinions known.

PHOTOS: Kim's best booty shots

The Glee star joined the rest of the world in logging on for a look at the famous Kardashian backside in all its glory on Tuesday, Nov. 11. But having stopped by to gawp, the newly married actress couldn't resist expressing her disapproval.

"I normally don't. But...you're someone's mother..." the 27-year-old actress commented on Kardashian's Instagram post, which displayed the naked cover shot from her sensational magazine spread.

Not that the bootylicious reality TV star is bothered. "Kim doesn't care, she just thinks it's funny," a source close to Kardashian told Us Weekly. "Naya is such a copycat, always doing whatever Kim does." See pics of the similarities between the two stars.

Indeed, Rivera does like to follow in Kardashian's footsteps. The brunette actress used Kardashian's hairstylist when she married husband Ryan Dorsey in September, and reportedly wore a dress similar to the 34-year-old's Givenchy wedding gown, that she wore for her marriage to Kanye West in May. We're thinking she might draw the line at nude butt modeling though!