Queen Elizabeth has eight grandchildren and the youngest, James, Viscount Severn, who is the son of the Earl and Countess of Wessex, just turned 13 years old on Dec. 17.

Christened James Alexander Philip Theo Mountbatten-Windsor, the Queen's youngest grandson, has such a unique royal title, and it's because of their father, Prince Edward.

According to Daily Express, Prince Edward didn't want James and his older sister, Lady Louise, 17, to have an HRH title like their cousins Prince William, Prince Harry, Princess Beatrice, and Princess Eugenie. Instead, he asked his mother, Queen Elizabeth, to style his children's name as the "children of an Earl" even though James and Louise are entitled to use HRH.

"Viscount" is apparently lower in the ranking to an "Earl" but above a "Baron" in the British peerage. There are over 270 viscounts in the United Kingdom, which typically equates to a "Lord."

When the right time comes, James stands to inherit his father's Earldom, while Prince Edward is set to inherit Prince Philip's title as the Duke of Edinburgh. It follows that James could also inherit this Dukedom upon his father's death.

The title of "Severn," on the other hand, is based on the Countess of Wessex's side of the family. It's inspired by the River Severn in Wales as Sophie has both Welsh and Scottish family history.

In an old interview, Sophie said that their children could decide at 18 years old if they want to retain their HRH titles as they chart their path as adults. This means that when James is of age, his name could change and be styled as His Royal Highness Prince James of Wessex. However, Sophie feels that her children will not likely choose to go down this path.

The Queen's teen grandson was the first baby to wear the replica of the royal family christening gown, which is passed on to every royal infant. The original gown was made for Victoria, Princess Royal, the daughter of Queen Victoria, in the 1840s.

James is currently a student of the Eagle House School in Berkshire. While he's not officially given royal duties, the teenager is slowly taking over some of the activities his grandfather, Prince Philip, used to enjoy, such as flipping the burgers during their family picnics or leading fly-fishing at Balmoral.

According to sources, these two activities are Prince Philip's domain but James is proving to be the rightful successor. Eventually, however, James could gain more responsibilities as part of the royal family.