The invites have been sent out and the photographer's been appointed.
And now the all-important decision of who will design the wedding party's headgear has been taken.
Award-winning milliner Philip Treacy
has a long-standing affiliation with the royal family, having designed Kate Middleton
's hat for Prince William
's passing-out parade at Sandhurst in 2006.
Royal Ascot is usually marked by pictures of Princesses Beatrice
and Eugenie in his daring creations.
And in 2005, he was commissioned to create the two striking headdresses worn by the Duchess of Cornwall
on her wedding day.
With a star-studded client list including fashionista Sarah Jessica Parker
and a style which blends elegance with a whimsical sense of fun, Philip is a clever choice for the bride.
Although Kate is likely to be wearing a veil on her special day she may want a more glamorous accessory for the evening as she's apparently considering a change of outfit.
Philip may also be designing hats for the senior ladies of the wedding party, such as Kate's mother.