The prestigious title of Prince of Wales is not automatically inherited; Prince Charles must decide whether to bestow this title upon Prince William's accession to the throne. Nevertheless, it is likely that Prince Charles will bestow this title on his eldest son, and that the current Duchess of Cambridge will become the Duchess of Wales.

Camilla Parker-Bowles currently holds this title, but she does not use it out of respect for the former Duchess of Wales, the late Princess Diana.

With Kate Middleton expected to become Princess of Wales, a source told The Telegraph (via the Express) that the title change will bring mixed emotions to William. The source told the magazine, "It's definitely going to be a bittersweet moment."

"This is her [Princess Diana's] son and his wife, so in a way it will bring it full circle, but it will also be a painful reminder of what we have all lost."

No matter how difficult this moment will be for Prince William, royal experts and the public alike seem to agree that Middleton, who just turned 40, is more than ready for her future role, having gained confidence by leaps and bounds over the past decade.

"She is always seen with a very open and honest smile, indicated by the visible crow's feet tracks around her eyes," body language expert Darren Stanton previously told Marie Claire (on behalf of Be My Bet). 'When they smile, their whole face tightens up and you can see that they are developing a great deal of confidence, not only as royalty and public figures, but also as parents.'