Royal wedding etiquette: What to wear
Royal weddings are full of protocol but what are guests expected to wear for Prince William and Kate Middleton's big day?
The invitation states guest should wear "uniform, morning coat or lounge suit". But what does that mean?
Only active members of the armed forces are allowed to wear military uniform and need permission from a commanding officer to do so.
According to etiquette experts Debretts: "Each regiment has its own traditions and protocol for weddings. For instance, in some... it is not customary to wear uniform at all, and swords may or may not be worn."
If speculation is correct and Prince William wears his RAF uniform, then his brother, as best man and an officer with the Household Cavalry, would be expected to wear his military attire too.
Men are expected to wear a grey or black morning coat, with a grey or yellow waistcoat and striped grey trousers. Add to this a grey top hat, to be worn when outside, or carried under the arm when indoors. Top hats should be removed for official photographs. Gloves matching the waistcoat should be carried.
Debretts Guide to Wedding Etiquette advises against a backless waistcoat as this prevents the wearer from removing his coat. Ties should be worn, or a cravat with a pin, along with a plain shirt and cufflinks. Shoes should be black and lace-up.
For ladies this dress code means smart day dress - a suit, or a dress with a jacket, with hat and gloves, high heels and a matching handbag.
For men, this means a plain business suit, worn with a discreet collar and tie.
Ladies should wear a smart day dress. Hats are not compulsory - in fact at the wedding of Prince Edward to Sophie Rhys-Jones the wearing of hats was discouraged.
And this word of warning from Debretts: "It is notoriously difficult to socially kiss while wearing a wide-brimmed hat. There is a knack to tilting the head at a suitable angle, but two ladies both in wide-brimmed hats should avoid such an 'intimate' greeting."