Harry's big match with Meghan a headache for William

Meghan and Harry name the day. Photo / AP

It is one of the greatest spectacles of British life: two perfectly matched sides watched by tens of thousands of people, all hoping for a happy outcome.

But away from the FA Cup final, the minor occasion of a royal wedding will be taking place. About 32km away from Wembley, on Saturday May 19, Prince Harry will be marrying Meghan Markle at Windsor Castle.

One guest who might find this clash of dates problematic is Prince William — who is likely to be his brother's best man and as president of the Football Association he usually presents the trophy.

Next year, the FA has conceded, it will have to find someone else to do the honours.

Harry and his fiancee are bucking royal tradition by choosing a Saturday to wed. Kensington Palace aides have already said the wedding will reflect the couple's "characters and personalities" and be a moment of "fun and joy".

They will say "I do" in the 15th century St George's Chapel. It is likely to be a morning ceremony, which would avoid a television clash with the Cup final, and will take place a month after William and Kate are due to welcome their third child.

Markle's parents Thomas Markle and Doria Ragland will attend the wedding and Prince George and Princess Charlotte are expected to be a pageboy and bridesmaid.

American actress Markle is set to spend Christmas with Prince Harry and the royal family at Sandringham.

The move is a break in tradition, with partners previously having to wait until they are married before being allowed to spend Christmas with the Queen and the rest of the family in Norfolk.