The Duchess of Cornwall will be joining her sister-in-law, Princess Anne, for a rare royal engagement next week.

Clarence House has announced that Camilla, the Duchess of Cornwall will be attending a special graduation ceremony at the University of Aberdeen, of which she is a Chancellor. She will confer the honorary degree of Doctor of Laws upon the Princess Anne, also known as Princess Royal.

The princess is being honoured by the 72-year-old for her outstanding contribution to public life and sport for more than four decades, with much of her work relating to education and charities based in Scotland, reports Hello. Apart from Anne, Professor Janet Darbyshire will be receiving the honorary degree of Doctor of Science for the significant impact she has made in clinical science over the past 40 years.

The formal ceremony that is scheduled for Tuesday, January 14 will be attended by around 400 guests, including university alumni, staff, students, supporters and civic and industry leaders.

Anne is considered one of the most hardworking royals, often being crowned the hardest working royal in a statistic released by a man named Tim O'Donovan from Dorchet, who has been counting the number of the royal family's numerous engagements since 1978. However, for once, the 69-year-old came second in 2019 with 506 engagements as her elder brother Prince Charles beat her with 521 engagements, reports Vogue.

This morning, The Prince of Wales and The Duchess of Cornwall joined The Queen and other members of the @RoyalFamily at the Christmas morning Service in Sandringham. 🎄 pic.twitter.com/FuRIPEnFkW

— Clarence House (@ClarenceHouse) December 25, 2019

The last time Anne and Camilla were seen together was in December, at the Christmas morning service in Sandringham, where the royals wore strikingly similar outfits. Not only the royals pitched up wearing similar shades of purple, but both of them were also wearing dress coats, similarly shaped hats, and the same pair of long black boots. The princess royal and the duchess were captured meeting each other outside of the church and appeared to laugh the coincidence off on realising the clash.

Trooping The Colour 2016
(L-R) Zara Tindall, Anne, Princess Royal, Camilla, Duchess of Cornwall, Charles, Prince of Wales, Catherine, Duchess of Cambridge, Princess Charlotte of Cambridge, Prince George of Cambridge, Prince William, Duke of Cambridge, Prince Harry, Queen Elizabeth II Prince Philip, Duke of Edinburgh and Sophie, Countess of Wessex watch a fly past during the Trooping the Colour, this year marking the Queen's 90th birthday at The Mall Ben A. Pruchnie / Stringe

Women of the royal family are usually advised as to what shade the queen will be wearing to avoid a clash. Though all the royals managed to avoid a clash with Queen Elizabeth II who arrived wearing a coat in bright red, Anne and Camilla ended up having an awkward clash.