A pair of ruby red slippers worn by actress Judy Garland in the classic movie The Wizard of Oz is set to be auctioned off Saturday.

The iconic sequinned pumps were once stolen from a Minnesota museum. But now they are expected to fetch as much as $3m (£2.35m) at auction, according to Heritage Auctions.

Online bidding started a month ago, and as of noon local time on Saturday, the highest bid was $1.55m.

Heritage Auctions has called these slippers the "Holy Grail of Hollywood memorabilia".

Garland was only 16 when she played Dorothy in the classic 1939 musical The Wizard of Oz. Media outlet Variety ranked it second in its inaugural list of "100 Greatest Movies of All Time".

The film is a musical adaptation of L. Frank Baum's 1900 children's book The Wonderful Wizard of Oz. While in the book, the magical slippers are silver, the producers for the film changed them to red to take advantage of the new Technicolor technology.

In the film, as in the book, a pivotal moment occurs when Dorothy must click her heels three times as she repeats "There's no place like home" in order to leave the magical land of Oz and return to Kansas and her Auntie Em.

While several pairs of shoes were worn by Garland during filming, only four are known to have survived.

One of the pairs is on exhibit at the Smithsonian's National Museum of American History. But this pair up for auction has its own unique history.

Collector Michael Shaw had loaned the slippers out to the Judy Garland Museum in her hometown of Grand Rapids, Minnesota when they were stolen in 2005.

Professional thief Terry Jon Martin used a hammer to smash the glass case and snatch the slippers, believing that their insured value of $1m must be because they were covered in actual gemstones.

But when he took them to a "fence" - an intermediary who sells stolen goods to discreet buyers - he discovered they were just glass.

So he gave the shoes to someone else. It wasn't until 2018 that the FBI recovered the shoes in a sting operation. What happened to them in those 13 years is still not known.

In 2023, Martin - who was in his 70s and used a wheelchair - pleaded guilty to stealing them, and was sentenced to time served.

"There's some closure, and we do know definitely that Terry Jon Martin did break into our museum, but I'd like to know what happened to them after he let them go," John Kelsch, curator of the Judy Garland Museum, told CBS News Minnesota in 2023.

"Just to do it because he thought they were real rubies and to turn them over to a jewellery fence. I mean, the value is not rubies. The value is an American treasure, a national treasure. To steal them without knowing that seems ludicrous."