妮可．基德曼怎么了？为何肿着脸来戛纳？

When Nicole Kidman arrived in Cannes on Monday night to promote her new movie Grace of Monaco, we were all a bit confused.

Mainly because the 46-year-old actress looks completely different to the last time we saw her.

The blonde Hollywood star's face looked oddly puffy when she arrived on the red carpet at the world-famous film festival.

The Australia actress, who showed off her slender frame in a black bodycon dress, wore her hair scraped back off her face, which highlighted her bizarre complexion.

But Nicole seemed oblivious to the difference in her appearance, and spent the evening smiling for photographers and blowing kisses at her fans.

Last year, the mum-of-two told Italian newspaper La Repubblica she would never have surgery.

"No surgery for me; I did try Botox, unfortunately, but I got out of it and now I can finally move my face again," she said.

The Australia actress led the way as a host of A-list Hollywood stars arrived in the south of France for the start of Cannes Film Festival on Tuesday night.

The opening film - "Grace of Monoco" stars Kidman as the Hollywood actress Grace Kelly who became the Princess of Monaco when she married Prince Rainier, and died following a car crash in 1982 in the hills of the principality.

There are 18 films in competition for the coveted Palme d'Or, which will be handed out along with other prizes at the end of the festival on May 24.

Kidman and other stars will ascend the famous red carpet tonight to the cinema inside the Palais des Festivals et des Congres for the glittering opening event under the watchful eye of the world's media, which has staked out viewing spots and parked stepladders for photographers days in advance.

It is a huge draw for the industry and public alike, with an estimated 127,000 visitors expected, plus 30,000 accredited professionals, 4,000 journalists and 700 technicians, according to a periodical distributed by the festival.

Last year some of those who attended the festival were less than welcome, having made off with jewels worth several million dollars.

The security presence this year is conspicuous, with dark-jacketed men standing outside or immediately inside fancy boutiques.

Even if Cannes remains the one event on the crowded film festival calendar that the big players most want to attend, a senior editor at US entertainment magazine Variety said it was scaling back.

"You see Cannes scaling back. And you see it ... for Cannes, for Cannes standards it's a little smaller than Cannes usually is," Ramin Setoodeh said.

"That said, it's still a very big festival, you have stars from Nicole Kidman to Robert Pattinson, to Kristen Stewart, Ryan Gosling had his directorial debut here at Cannes. So it's still a pretty big festival, it's just not as big as Cannes has always been."