She was an icon in both her royal capacity as well as her fashion sense, and today one of the late Lady Diana Spencer’s dresses is being auctioned off.

Princess Diana’s black taffeta gown, worn during her first official appearance with her then-fiancé Prince Charles is up on the block at Kerry Taylor Auctions in London, England.

According to industry experts, Diana’s dress is expected to fetch a tidy sum, somewhere in the neighborhood of $150,000.

Designer Elizabeth Emanuel explained, “This was really a shadow of what she was to become in terms of a fashion icon. It was the first time that people had seen her looking like a princess. Like a movie star. And grown up.”