Mann joked to USA Today that she is becoming more and more dissatisfied with her looks with each passing year.
"I had a nervous breakdown. I look at myself and things look different," she explained. "My skin looks different. My elbows, I have weird skin on my elbows I never had before. I have more wrinkles."
Her husband Judd Apatow made light of his wife's worries by suggesting that she have a radical cosmetic procedure.
"She's going to have elbow-tightening surgery," Apatow quipped.
Apatow previously revealed that he fell in love with Mann the very first time he met her at auditions for his 1996 film The Cable Guy.
This is 40 is released on December 21 in the US and February 14, 2013 in the UK.
Watch a This is 40 trailer below: