Meghan Markle and Prince Harry upset royal fans for failing to address Prince George appropriately in their birthday greeting.

On Monday, Prince William and Kate Middleton’s eldest son celebrated his sixth birthday. The third-in-line to the throne was flooded with warm wishes from royal fans and other members of the royal family.

The Duke and Duchess of Sussex didn’t miss to celebrate their nephew’s birthday by commenting on Prince George’s photo with a sweet note, “Happy Birthday, Wishing you a very special day and lots of love!”

However, many weren’t impressed with the way Prince Harry and Markle greeted the future king because they didn’t address him properly, E! News reported.

“He is the future KING. Treat him with respect. He is HRH!!!!!!!” one fan commented.

“He is HRH Prince George to you!!!! Don’t forget to mention!” another furious netizen added.

A different netizen pointed out how the other members of the family including Clarence House and The Royal Family included “Prince George” in their birthday greetings for the 6-year-old royal.

“When all the royal accounts have [used] a 'prince' except yours…so there is really something,” the online user added.

Meanwhile, some netizens tried to defend Prince Harry and Markle by saying that the critics were just trying to find fault where there is none. Also, Prince Harry and Markle are Prince George’s uncle and aunt, so there’s no need to write his title.

This isn’t the first time Prince Harry and Markle were slammed after greeting a royal on his birthday. Last month, the Duke and Duchess of Sussex were also criticized for leaving a very formal birthday message to Prince William.

Prince Harry and Markle didn’t make a separate post but commented on Kensington Palace’s post about Prince William. The couple just wrote, “Happy Birthday to the Duke of Cambridge,” which many deemed as a “cold” and “useless” birthday greeting.

Royal expert Ingrid Seward also felt that Prince Harry and Markle’s greeting was a deliberate snub to Prince William because their birthday greetings to Prince Philip and Queen Elizabeth II were more personal and warm.

“I think it’s a snub if they don’t leave one for Prince William as they did for the Duke and for the Queen,” the Majesty Magazine editor said. “If they don’t I think it’s pretty rude and will certainly be construed as purposeful.”

Meghan Markle Prince Harry
Prince Harry and Meghan Markle are pictured leaving Westminster Abbey in London after Commonwealth Day Services on March 11, 2019.  Ben Stansall/AFP/Getty Images