And she's not the only one. Nicely rounded celebrity bellies are now being flaunted with a perky, so-what sensuality that makes yesterdays anorexic washboards look painfully impoverished. A radiant, post-childbirth Madonna; Bjork, her paunch often seen peeking out from a cut-off top; Sandra Bullock, who has waxed lyrical about her love of a well-pronounced tummy; Sophie Dahl and Alicia Silverstone, who can hardly be called svelte.
But it is to another English actress that we should turn for confirmation of changing attitudes. For years, Helena Bonham Carter was typecast in frumpy Edwardian film roles. You would never even get a flash of an ankle, let alone a glimpse of her stomach. Then came Wings of the Dove and a change of heart. Helena bared all - boobs, bum, the lot. And there in the middle, gently plumped like a favourite pillow, a normal, rounded, womanly pot.
According to Wayne Hemingway, head of design at Red or Dead, this is not soon enough. People are bored, even repulsed, by washboard stomachs on models, actresses and pop stars - especially if the navel has been "stretched", as he puts it, in a riot of piercing. "Women with bellies look like they're proper women," he says, "like they could have a child in there to add to the human race."
In her book, Women on Sex, the relationship psychologist Susan Quilliam reported that up to 98 per cent of females were unhappy with their midriffs. "To have a flat tummy is the only way to be," she says. Quilliam traces this back to the Sixties and a misreading of feminism whereby "being one of the lads, an equal companion as opposed to a wife, meant having a stomach like them".
But history shows we have been bucking an historical trend. Rubens nudes were thought highly sensual. Some of the most sublime representations of women in art - the sculpture of Rodin, Renoir's nudes - have had a pot. Belly dancing, for all its seedy connotations in Britain, is an age- old erotic art. Finally, in the Nineties our perceptions of womanly beauty may be veering back from the pinched and preened towards the natural. So all eyes will be on Kate's Oscar frock. Here's hoping it clings in all the right places.