Nicole Kidman may have had lip surgery

Australian actress Nicole Kidman has appeared on the cover of a US magazine sporting what looks like a new, fuller pair of lips.

The A-list star graces the front cover of Parade, a national Sunday newspaper magazine, with her lips looking remarkably more enhanced than in her younger years.

Celebrity news site Entertainmentwise.com went so far as to state that she had "what can only be described as a plastic pout."

However, Kidman has not admitted to using cosmetic surgery to plump up her lips, an effect that's usually achieved through the injection of collagen or dermal fillers.

Earlier this month, the actress was criticised by Sharon Osbourne for denying that she used wrinkle-relaxing injections.

On the popular US chat show Chelsea Lately, the former X Factor judge claimed that Kidman's forehead looked like a "flat screen TV" due to all the Botox she had used.

She went on to encourage celebrities to admit to having cosmetic surgery, saying "If something bothers you, it doesn't make you happy, then change it. What's the deal? I don't get what the mystique is, why people lie about it."

Sharon has always been upfront about the numerous aesthetic procedures she has undergone, which have included a breast augmentation, liposuction, a tummy tuck and a facelift.

Kidman, however, has always been adamant that her youthfulness is due to health, not surgery. She recently stated: "I'm not enamoured with youth… My own sense of vanity is not that strong. I'm not a mirror person. But I like to look healthy - the youthfulness is in health. It's very important."