Britain's Sarah Ferguson believes Duchess Catherine is ''entitled to have a moment alone'' with her husband.

The Duchess of York spoke out after topless pictures of the Duchess of Cambridge were published in a French magazine and Sarah - who was once photographed topless and having her toes sucked by her lover - says she has ''total empathy'' for Catherine.

She told InTouch magazine: ''As you know, I've been there and have total empathy with the beautiful lady who does a beautiful job.

''Surely she's allowed to have a moment alone to be with her husband.''

After the images were first published earlier this month, Sarah was quick to rush to Catherine's defense, calling the incident ''devastating'' for the duchess, who was known as Kate Middleton before marrying Prince William.

She said: ''I have total empathy and sympathy for her. 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.

''She is a beautiful young woman doing a great job for the country. Why should she be stripped of that moment with her husband?''