Camilla, 77, and Anne have grown close since Her Majesty joined the royal family in 2005 following her wedding to King Charles.

Princess Anne, who is widely known as the hardest working royal, appears to also be a stickler for the rules because, the royal just refused to break protocol even with Queen Camilla 's permission. On Wednesday, Camilla was presented an honorary doctorate of literature by her sister-in-law Princess Anne.

Princess Anne and Queen Camilla made a rare public appearance together earlier this month, with one expert claiming the Princess Royal showed her true feelings

Her Majesty Queen Camilla was made an honorary doctorate of the University of London by the college's Chancellor, Princess Anne, on Wednesday, November 20. However, the important event was not without some humor as the Princess Royal found a royal protocol breach request from the Queen "hilarious.

Queen Camilla returned to royal duties for the first time since Buckingham Palace announced she had been diagnosed with a chest infection which affected her timetable

Princess Anne had a hilarious response when Queen Camilla invited her to break royal protocol during their joint engagement on Wednesday. Yesterday, November 20, the pair conducted a rare engagement at the University of London’s Foundation Day.

Queen Camilla was presented with a special honor by none other than her sister-in-law, Princess Anne. Camilla, 77, was awarded an honorary doctorate of literature by The University of London on Wednesday0.