Kate Middleton has had Princess Diana's engagement ring resized to stop it from falling off.

The brunette beauty is set to marry Prince William on April 29 and while she was thrilled when he presented her with his late mother's band when he popped the question last year, Kate decided to make the alteration because she was terrified it would fall off during the ceremony.

A source said: "The band was turning. Kate absolutely adores it and didn't want to cause a fuss.

"A bride's worst nightmare is looking down and seeing her ring has fallen off. One can only imagine how this is magnified when you are marrying the future King of England."

Kate has now asked Crown jewellers G Collins and Sons to attach two tiny platinum beats to the inside of The Ring to make it a size I, one step up from Kate's size H finger, to make it comfortable.

The £32 million ring was given to William by Kate after the pair got engaged in Kenya last October so that his mother Diana - who was killed in a Paris car crash in 1997 - would be part of their big day.

Kate and William will marry at London's Westminster Abbey in front of 1,200 guests including David Beckham and his wife Victoria and Sir Elton John and his husband David Furnish.