Prince Harry best man, Pippa Middleton maid of honor at U.K. royal wedding

The announcement was made Monday by St. James' Palace, the office for Princes William and Harry, confirming expectations for the highly anticipated nuptials at London's Westminster Abbey.

The 26-year-old Harry has shed his partygoing image for that of a military man in recent years, and Pippa Middleton, 27, had long been the favorite for that position because of her extremely close relationship with her 29-year-old sister.

“It's completely natural,” said royal historian Hugo Vickers. “Normally, a member of the royal family has his brothers as his supporters, or joint best men. As Prince William has only one brother, and he is very close to Harry, it's an obvious choice.”

Since Prince Harry loves to tease his older brother, his toast to the newlyweds is expected to be one of the highlights of the celebrations. Will he poke fun at William's receding hairline? Will he mention other girls who once attracted William's eye? Stay tuned.

Vickers was slightly surprised by the choice of Pippa Middleton, whose formal name is Philippa, since it is not customary for royalty in England to have bridesmaids who are not children.

“There was a lot of conjecture about her age and whether she might be too old for the role of the chief bridesmaid,” said Joe Little, managing editor of Majesty magazine. “But considering how close the sisters are, it was really a foregone conclusion.”

Little also said Prince William had been expected by some to choose more than a single best man, as has been the case in earlier royal weddings.

“It's unusual to have only just one man,” Little said. “All of the queen's sons — Charles, Andrew, Edward — had two supporters at their wedding. But obviously William doesn't feel the need to have more than one supporter and it's by no means a hard and fast rule.”