The ad for L'Oreal's Feria hair highlighting product sparked outrage when it appeared in the current edition of Elle magazine because the singer, whose father is African American and mother is Creole, looked almost completely white with strawberry blonde hair.
The New York Post said that the ad was shocking in a piece called 'Beyonce the Pale' and that she looked like a "weird, nearly white version of herself".
Celebrity website TMZ claimed the ad had been "severely photoshopped" and set up a poll asking its readers "Is the ad a slap to blacks?"
One of its readers left a comment saying: "Shame on L'Oreal for doing this. I see no excuse for this. If it was uneven skin tone then they just as easily could have made her a tone darker but they did not do that. They made her white."
L'Oreal has denied that the company digitally altered Knowles' complexion. A spokesperson for the cosmetics giant said: "Beyonce Knowles has been a spokesperson for the L'Oreal Paris brand since 2001. We highly value our relationship with Ms Knowles. It is categorically untrue that L'Oreal Paris altered Miss Knowles's features or skin-tone in the campaign for Feria hair colour."
Some fashion experts have said that the ad is a sign of negative attitudes within the fashion industry towards women with darker skin.
The Voice, Britain's best-selling black newspaper, said that it would be "disgusted" if the image had been "whitewashed".
Knowles has a contract with L'Oreal worth £2.3m over five years. Her representative declined to comment beyond L'Oreal's statement.