05/18/2012 05:59 pm ET

Charlotte Casiraghi, Royal & Gucci Girl, Hangs Out At Cannes Film Festival 2012 (PHOTOS)

While most of the royals from around the world were day-drinking at Windsor Castle today (seriously, most of them), one of Monaco's royal darlings was at a different party, hanging out south of London at a wee little film festival called Cannes.

The celebs were out in full force today in the south of France, taking time out from their packed roster of indie film screenings to catch a little light-hearted flick around noon: DreamWorks' "Madagascar 3: Europe's Most Wanted."

Some celebs, however, went to see a more erudite flick: a re-release of the Sergio Leone’s 1984 film "Once Upon A Time In America," sponsored by the Gucci Film Foundation. Gucci girls Gemma Arterton and Natasha Poly were in attendance, as well as Jane Fonda, Naomi Watts and Salma Hayek, who looked lovely in a sparkly -- you guessed it -- Gucci dress..

But the lady that most caught our eye on the red carpet was Charlotte Casiraghi, the 25-year-old daughter of Princess Caroline of Monaco and granddaughter of Princess Grace of Monaco, who gave the premiere a little royal flair in her deep green ruffly Gucci fall 2012 dress. And in her long wavy hairdo, we can't help but think Charlotte resembled another royal who did some socializing today.

Casiraghi, a model who's covered Vogue Paris, is also the fresh new face of Gucci.

Check out photos of Charlotte -- and all the celebs -- below!