The 'Judas' singer responded to photographs from her 'Born This Way Ball' tour, in which she appears to be sporting a fuller frame, by posting a quotation associated with Marilyn Monroe on her Little Monsters site.
The saying reads: "To all the girls that think you're ugly because you're not a size 0, you're the beautiful one. It's society who's ugly."
GaGa included a message of her own alongside the post, saying: "Thank[s] to my fans who love me no matter what, and know the meaning of real beauty&compassion. I really love you."
The musician later rewarded French supporters by joining them for a picnic outside a Sephora store in Paris to celebrate the success of her debut perfume Fame.
GaGa previously blamed her weight gain on the food at her father's Italian restaurant in New York.
The change in GaGa's figure last week led Kelly Osbourne to speculate that the star, who is currently dating Vampire Diaries actor Taylor Kinney, could be pregnant.