Pop star Solange Knowles has vowed to cover up for the rest of 2009 after suffering an embarrassing fashion mistake on Monday which left her nipple exposed.

Pop star Solange Knowles has vowed to cover up for the rest of 2009 after suffering an embarrassing fashion mistake on Monday which left her nipple exposed.

Beyonce's younger sister was attending the Toni Maticevski show for New York Fashion Week wearing a low cut black dress with a sheer material covering her chest and shoulders.

But the dark underlay slipped down at some point during the night and left Knowles' left nipple on display for all to see.

And the 22-year-old is horrified by the wardrobe blunder because she is rarely caught off guard.

Writing on social networking site Twitter.com, she says: "I always wear undies, never been carried out of the club drunk, I won't even pose for King (men's magazine) or any 'eye candy' type shoots and now look ... my s**t on display for all the world to see ..."

Knowles is also annoyed at people's attempts to comfort her.

"Why does everyone always wanna say, 'It could've been worse' when this type of thing happens?"

Meanwhile, Pretty Woman star Julia Roberts is dreaming up a dinner date with the new US President and his wife - because she thinks her kids will make great pals for the power couple's daughters.

The actress told the publication she would cook "a big chicken tagine with figs and apricots" for her guests. - Wenn