The Duchess of Cambridge has been a member of the royal family for eight years now, but she's only just received this special honour from the Queen.
On Monday, to mark Prince William and Catherine's eighth wedding anniversary, Buckingham Palace announced that the Duchess had been made a Dame Grand Cross of the Royal Victorian Order by the Queen.
It's the highest honour that can be given to a female member of the royal family, and was given for Catherine's "services to the Soverign", during her time as a Duchess so far.
The honour is considered to be a huge achievement in the world of the royals, and many royal watchers understand it to be the ultimate recognition of Catherine's personal contribution to the family and the Queen.
The Duchess of Cambridge's special award is something other female members of the royal family have also been granted.
Camilla, Duchess of Cornwall, won the accolade herself in 2012 after seven years of marriage to Prince Charles, and so seven years of royal service - while Sophie, Countess of Wessex, got hers after being married to Prince Edward for 10 years.
The Royal Victorian Order was founded way back in 1896, by Queen Victoria, as a way of rewarding the personal service of people to the monarchy.
Kensington Palace haven't officially commented on Catherine's achievement, but a palace source told royal reporters, "Her Royal Highness is honoured and looks forward to continuing her work in support of the Queen".
It's already been a busy - but special - week for the Duchess of Cambridge, and that's only set to continue. Of course, she and husband Prince William celebrated their eighth wedding anniversary on Monday, with Kensington Palace posting a series of sweet photos of their wedding to mark the occasion.
Last week, the Cambridge family also celebrated Prince Louis' first birthday - and on Thursday, their only daughter, Princess Charlotte, will turn four!
It's likely that the family will celebrate the happy day privately, as they did with little Louis, although they will most probably release birthday photos of the Princess - so that's something exciting to look forward to!