Princess Kate and Prince William share sweet message for Lady Louise as she turns 21

The Prince and wished a happy birthday today, as the young royal

Princess Kate and Prince William took to social media to share a sweet message for Prince Edward and Duchess Sophie's eldest child.

On the couple's official X account, Kate and William re-published the , and accompanied it with their own message.

It read: "Wishing Lady Louise a very Happy 21st Birthday"

It also featured three emojis featuring a balloon, a birthday cake and a letter.

It comes minutes after Buckingham Palace announced the Princess of Wales's attendance at two major events this weekend.

On Saturday, Princess Kate will head to the Royal Albert Hall , a stunning and poignant concert paying tribute every year to those who gave their lives to keep Britain safe.

The following day,, to attend the Remembrance Sunday service, the palace confirmed.

On both occasions, Kate will be joined by - although the Prince of Wales is expected to play a more active role during the service on Sunday, with his wife instead attending the sombre ceremony from one of the Foreign Office's balconies overlooking the Cenotaph.

On Sunday, the heir to the throne will lay the wreath previously laid by King Charles as the former Prince of Wales, featuring The Prince of Wales's feathers. The wreath bears a new ribbon in Welsh red.