Britain’s Queen Elizabeth II said  she was appointing her daughter-in-law Camilla, a member of the ancient Order of the Garter, in an apparent boost to her royal standing.

The monarch announced she was adding Camilla, the wife of the heir to the throne Prince Charles, to the royal members of the Order, who currently include her children Charles, Anne, Andrew and Edward and her eldest grandson Prince William — but not their spouses.

The inclusion of Camilla, who married Charles in 2005, comes as she has taken on more prominent royal duties in recent years and has seen her public approval rating grow.

The Most Noble Order of the Garter is the oldest order of chivalry in the world, established in 1348 by the queen’s ancestor King Edward III.

Its members are called knights and ladies.

They attend an annual service at St George’s Chapel in Windsor Castle, walking in procession wearing white ostrich plumes, blue velvet robes and black velvet hats.

The order includes a maximum of 24 non-royals personally chosen by the monarch.

It is Britain’s highest honour and is awarded for outstanding public service and achievement.

The Queen on Friday also appointed former Labour prime minister Tony Blair as a Knight Companion of the Most Noble Order of the Garter, the highest British civil honour obtainable.

He will join former Conservative prime minister John Major who was awarded the honour in 2005.