King Charles gives Prince William a military title with close ties to Prince Harry

King Charles III has handed over a military role he held for three decades to Prince William in a move that is sparking controversy because of the role's close ties to Prince Harry.

Charles on Monday presented William, his eldest son, with the title of Colonel-in-Chief of the Army Air Corps in a military ceremony at the Army Aviation Centre in Hampshire, England.

With the title, William is now the head of the regiment that his younger brother, Harry, served in during his time in the British Army.

Harry, who now lives in the United States, served as a British Army officer for 10 years.

During his decade of military service, which ended in 2015, Harry rose to the rank of Apache helicopter commander. Known as Capt. Harry Wales in the Army, he was deployed to Afghanistan twice, from 2007 to 2008 and then again from 2012 to 2013.

In 2012, the British Defense Ministry named Harry the best front-seat pilot, or co-pilot gunner, from his class of more than 20 fellow Apache helicopter pilots.

Following the military ceremony Monday, William flew in an Apache helicopter as he left the base as the new Colonel-in-Chief of the Army Air Corps.

The ceremony was held less than one week after Harry traveled to London from his home in California to mark the 10th anniversary of the Invictus Games, a Paralympic-style competition for wounded service members that he founded in 2014.

None of Harry's royal family members joined him at a service of Thanksgiving for the Invictus Games held at St. Paul's Cathedral on May 8. However, his maternal uncle and aunt, who are siblings of the late Princess Diana, attended the service.

On the same day the service was held, Charles attended a garden party at Buckingham Palace, and William led an investiture ceremony at Windsor Castle.

At the time, a spokesperson for Harry told ABC News that Charles' schedule would not allow time for him to see his younger son during his London visit.

"It unfortunately will not be possible due to His Majesty's full programme," the spokesperson said of a meeting between Harry and Charles. "The Duke of course is understanding of his father's diary of commitments and various other priorities and hopes to see him soon."

A spokesperson for both Buckingham and Kensington Palaces declined to comment to ABC News.

The last time Harry and Charles saw each other was in February, when Harry flew to London to visit Charles after the palace publicly shared that Charles had been diagnosed with an undisclosed type of cancer.

Prior to that visit, Harry had not seen his 75-year-old father since the king's coronation last May at Westminster Abbey.

Harry is also not known to have seen William -- with whom he has a strained relationship -- since the coronation, during which William played a major role and Harry sat in the audience with other royal family members.

Harry stepped down from his role as a senior working royal in 2020. Since then, he and his wife Meghan, the Duchess of Sussex, have settled in California with their two young children, Archie and Lilibet, and become financially independent, taking on new roles in the entertainment and philanthropy worlds.

The Sussexes on Sunday completed a tour of Nigeria, which came at the invitation of the country's Chief of Defense Staff, its highest-ranking military official.

Much of the trip focused on Harry and Meghan's interactions with Nigeria: Unconquered, a nonprofit organization that is affiliated with the Invictus Games.

Harry also met with injured service members at a local military hospital during the three-day visit.