But do their coats match? The eleven horses of the Metropolitan Police's Grey Escort, nine of them will escort William and Kate's carriage from Westminster Abbey to Buckingham Palace on Friday William and Kate's first journey as husband and wife will be escorted by nine of the coolest heads the Metropolitan Police has to offer - the force's famous grey horses.
But while the matter of invites has long been settled for human guests at the wedding, the animals of the Met's Grey Escort are still waiting to learn if they will have the honour of accompanying the royal couple's carriage.
The force has selected 11 horses with the calmest temperaments to escort the royal carriage from Westminster Abbey to Buckingham Palace after the wedding but only nine will actually step onto the Mall on the big day.
And while guests must worry about what to wear - the horses of the Grey Escort are also assessed on whether their coat will match their peers.
Hard at work: The horses are being put through their paces at the Met's mounted division headquarters in Ditton, Surrey, left. Lucy Davies holding her mount Benjamin in the ceremonial dress, rightGrey Escorts are used in several high-profile ceremonial events.
All the animals, which have to be grey in colour, are used as operational police horses and work on general patrols and cover events such as football matches.
On the big day the horses and officers will not purely be used in a ceremonial capacity, but they will also assist in the event of an incident.
A selection process has identified the best 11 greys for the job. They have demonstrated a calm temperament and are now in the process of being put through various exercises and routines.
The extra two horses have been selected to ensure there is sufficient cover.
The Mounted Branch has led processions for many years including Princess Diana's wedding, the Duke of York's wedding, the funeral of the Queen Mother, Trooping the Colour and some state visits.
Long-standing role: The Met's Grey Escort at the Queen's coronation. The horses are a central part of many official engagements 
Standing by: The horses will also be used to control crowds should anything go wrong on the big daysource: dailymail