"Disaster" and "humiliating".

That's how Gwyneth Paltrow branded her show-stopping dress at this week's Iron Man 3 premiere in Hollywood.

The 40-year-old, who had been crowned the World's Most Beautiful Woman by People magazine ahead of the racy red carpet appearance, spoke about the revealing Antonio Berardi dress in an interview with TV talk show host Ellen DeGeneres.

The star admitted she was horrified to discover her "*** was hanging out" and also said she needed grooming before putting it on, the Daily Mail reported.

"Yeah, oh, I kind of had a disaster," she told the host in an interview set to air in the US on Friday.

"I was doing a show and I changed there and I realised I couldn't wear underwear. I don't think I can tell this story on TV... Well, let's just say everyone went scrambling for a razor… So I went from being the most beautiful to the most humiliated. In one day…"

Paltrow plays Pepper Potts alongside Robert Downey Jr in the Iron Man film trilogy.

The dress featured mesh panels that showed off her bare sides, sparking a storm among fashionistas.

It also polarised opinion. Ms Mira Taylor, a fashion designer from London, tweeted: "Love Gwyneth Paltrow's 'no underwear don't care' look. Only she can pull this off with class!"

But Ms Erica Taylor from New York wrote: "Gwyneth, get a new stylist! I'm hating this. #noonecaresforgotunderwear."

The dress drew comparisons with "that dress" worn by actress Elizabeth Hurley to the Four Weddings and a Funeral premiere in 1994.

Her overtly sexual Versace outfit was held together with gold safety pins, with a deep cut-away section at the bosom. Paltrow also talked about finding out about getting People magazine's title.

She said: "My publicist of 22 years, Stephen Huvane, sent me an e-mail. And honestly I thought it was a joke. I reread it three times.

"I was like oh, he sent this to the wrong client. For a minute I really thought that someone was playing a joke on me."

But last week, Star Magazine declared the actress the most hated celebrity on the planet.

It may not really be Paltrow's look that got her the World's Most Beautiful Woman title, explained PR director Jamie Krauss at The Narrative Group.

"They just pick somebody that has something to promote and is going to give a really good interview," she said. "That's how celebrity culture works."

Paltrow, who is married to Coldplay frontman Chris Martin, was also criticised last week for a collaboration with designer Melissa Odabash, producing bikinis marketed at four- to eight-year-olds.

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