The Voice mentor piled on the pounds after filming wrapped on Burlesque last year, and following her divorce from husband-of-five-years, Jordan Bratman, last September.
A source told In Touch magazine that the 30-year-old singer has tried everything to get back to her former slim self, including enlisting the help of a personal trainer, a dietician, and even a hypnotist.
'Christina hates her thunder thighs,' said the insider, adding that her current tactic is to hide her curves behind black clothes.