Star Magazine published an image of Prince William's wife sporting a noticeably fuller figure on its October 1 cover accompanied by the headline "It's twins", claiming that she is "up to 125lb and showing".
However, Celebuzz has obtained a copy of the original photo, taken in Singapore on September 11 during the couple's Diamond Jubilee tour, and noted "distinct differences" between the two.
On Star's cover, Middleton's slim-fit dress appears to have been "blown out", as evidenced by a far smaller portion of the Duchess's left forearm being made visible. A ring is also missing from her right hand.
The claim comes mere days after long-lens pictures of Middleton topless during her holiday with Prince William were published in French Closer.
Despite prompting worldwide controversy, a lawsuit against Closer and a preliminary criminal investigation, the leaked images have since been reprinted by publications in Italy, Ireland, Denmark and Sweden.
Star also reported that Middleton was pregnant earlier this month, running a cover image of the 30-year-old wearing a loose belt around her midriff as evidence of her "expanding waistline".
The move was condemned by X Factor USA judge and eating disorder sufferer Demi Lovato, who declared that the photo could give young girls "body image issues".
A year of the Duchess of Cambridge:
Copyright: PA Images