Diana's wedding dress to be auctioned

Diana on her wedding day.

Princess Diana's spare wedding dress - made in case her first was damaged - is to be auctioned.

Diana tried on the ivory silk gown, an exact copy of the dress she wore, on the morning of her wedding, auctioneer Cooper Owen said.

The only difference between the dresses is that the actual one she wore had Queen Mary's lace sewn on to the front.

The dress is expected to fetch more than 50,000 ($133,000) at the December 7 sale in London.