Photographs of Middleton topless while on holiday in Provence appeared in the French edition of Closer, the Italian magazine Chi and the Irish Daily Star.
Ferguson, who was the subject of topless pictures published by The Mirror in 1992, has now commented on the scandal.
"I have total empathy and sympathy for her," she told the Daily Mail. "I have been there and know what it's like.
"Everyone is entitled to privacy. It is a devastating invasion of one's personal inner space. It is deplorable, abhorrent and despicable."
Ferguson added: "She is a beautiful young woman doing a great job for the country. Why should she be stripped of that moment with her husband?"
Lawyers for the Duke and Duchess of Cambridge are thought to be seeking an injunction to prevent further publication of the photographs and have also vowed to sue for breach of privacy.
Meanwhile, Kelly Osbourne has described the publication of the pictures as "disgusting".
Photo gallery - The Duke and Duchess of Cambridge continue their Diamond Jubilee tour: