A sweat-stained dress worn by Judy Garland in The Wizard of Oz could become one of the world's most expensive costume dresses if it sells at auction later this year for more than an expected $1 million.

Who could ever forget Dorothy Gale's blue-and-white gingham dress? It's one the most memorable dresses in film history, one as unmistakably American as a Kansas cornfield.

Even better is the tell-tale imprint of the iconic American actress/singer who wore it in the 1939 classic.

"What is great about this is it has signs of use: There are sweat stains around the neck, but it is still in fine condition,” Catherine Williamson, director of entertainment memorabilia at Bonhams, told the SWNS news service.

Bonhams is set to auction the dress, at a starting price of $1.2 million, at its "Treasures from the Dream Factory" sale on November 23 in New York.

If the dress hits this price tag, it will become one of the most expensive dresses in history — as much thanks to Garland's star quality as its prominence in a beloved film.

"Judy Garland is in the top tier for collectability alongside Marilyn Monroe and Audrey Hepburn, and this costume is in the top ten of dresses," Williamson says. "I think the market will be international."

Although Garland was a 17-year-old starlet at the time, the dress was designed to make her look closer in age to her 12-year-old orphan character. Wizard helped make her a global star, as famous for her troubles as her talent.

Williamson believes the universal appeal of Wizard will mean high levels of interest for this sale.

"The dress is one of those costumes which are instantly identifiable," she says. "You immediately know it was Judy Garland who wore it as Dorothy Gale in The Wizard of Oz. It is the costume she wears throughout the film, which is a great movie and the definition of a classic... It is a privilege to be selling it."

Demand for props and costumes from Wizard is at a high. Even a "test dress," which wasn't used on screen, sold for $245,265 last year at Bonhams, Williamson says.

The Lion costume, however, sold for a staggering $2.9 million.