Gwyneth Paltrow
Gwyneth's went without underwear for the risqué dress.

After being named the World's Most Beautiful Woman in People magazine, Gwyneth Paltrow is showing the world exactly why she walked away with the crown.

The 40-year-old Iron Man 3 actress sparked a frenzy when she arrived at the Hollywood premiere of the superhero action blockbuster in a daring dress that revealed her underwear-free bottom.

From a distance the floor-length Antonio Berardi gown appeared demure and sophisticated. But on closer inspection the deceptive green and silver dress featured mesh panels down the sides, that give teasing glimpses of her hips and backside.

Photographers on the red carpet were in for a treat when the mother-of-two posed side-on to show off her toned legs and pert derrière.

The wife of Coldplay frontman Chris Martin completed her risqué look with natural make-up and let her hair fall straight fall on her shoulders.

Paltrow, who dethroned pal Beyoncé in People magazine's annual Top 10 Most Beautiful list, credited her youthful looks to a healthy diet and lots of exercise.

She is the founder of lifestyle and clothing website and follows a five-day-a-week workout routine to keep her in shape.

"It makes me look younger and feel strong," she told the US magazine. "When I first started, I thought, 'I'll never be good at this. This is a nightmare.' But now it's like brushing my teeth, I just do it."