Princess Diana had a backup wedding dress that she never knew about

Princess Diana famously wore a wedding dress with a 25-foot (7.6m) train during the ceremony. Photo / Getty Images

Designer Elizabeth Emanuel reveals there was another dress waiting in the wings.

Princess Diana - who died in a car crash aged 36 in 1997 - famously wore a wedding dress with a 25-foot (7.6m) train when she tied the knot with King Charles in 1981 when he was the Prince of Wales.

But now designer Elizabeth Emanuel has revealed that a second dress was lined up in case the original was stolen.

Elizabeth - who designed the gown along with her former husband David Emanuel - told People: “Neither of us wanted to worry her. It was a complete secret. I was a bit neurotic, and I thought, ‘What happens if somebody breaks in and steals the dress or something spills or there’s a fire or it gets stolen?’

“So I thought, ‘I’m gonna make a backup dress’.”

The spare dress was white, unlike the actual wedding dress which was deep ivory. Photo / Getty Images

The spare dress was different to the original and came with slim sleeves that were more “fitted” to the princess’s arms but the fate of the gown remains unknown to this day.

She said: “It’s what made the dress so spectacular - it’s larger than life. [The second dress] was also white, not the deep ivory that the royal wedding dress was made of.

”I just thought, ‘If anything happens we’ll finish it off and have it ready. But it likely ended up on some sample rail. It probably got reused, torn up, thrown out, who knows? I call it ‘the dress that never was’.”

The designer recently reproduced the dress using old sketches for a virtual museum honouring Diana.

Museum director and curator Renae Plant said: “We never got to see that dress on Diana and we thought it would be lovely to envision it. You cannot put a price tag on history”.