All Smiles: Kate Middleton Attends First London Affair Afresh Since Topless Row
Kate Middleton and Prince William laugh as they sign the visitors book during a visit to Middle Temple in London. REUTERS/Chris Jackson

The Duke and Duchess of Cambridge should know a thing or two about etiquette.

The royal couple – who celebrated their sixth anniversary last Saturday (29 April) – received a huge amount of well-wishes in honour of the special day.

It feels like yesterday when Kate Middleton arrived at Westminster Abbey in that gorgeous lace wedding gown by Alexander McQueen in 2011.

Like any polite couple, Kate and Wills wrote to the individuals who took their time to personally congratulate them on their wedding anniversary with quintessentially English ''thank you'' notes.

The letters were also complete with a photograph of the couple taken on their trip to Bhutan last year.

Self-proclaimed photographer and history buff Paul Ratcliffe from Leeds revealed the insides of the special note after receiving it from the royal household.

He appeared pretty chuffed with his latest post, tweeting a snap of the letter with the caption: "Lovely Photo-Thank You Card arrived from the Duke & Duchess of Cambridge for their 6th Wedding Anniversary [sic] Lovely image by @ArthurJEdwards".

The letter reads:

"The Duke and Duchess of Cambridge are most grateful to you for the message you so kindly took the trouble to send on the occasion of their 6th Wedding Anniversary.

It was most thoughtful of you and Their Royal Highnesses send you their warmest thanks and best wishes."

How very fancy. And short.

The royal couple are well in tune with the world of social media, ensuring Kensington Palace posted a thank you message alongside their wedding photo on Instagram:

Thank you so much for all the lovely messages wishing The Duke and Duchess a happy sixth wedding anniversary. 📷PA.

A post shared by Kensington Palace (@kensingtonroyal) on

The caption read: "Thank you so much for all the lovely messages wishing The Duke and Duchess a happy sixth wedding anniversary."

Kate and Wills' adoring fans commented on the snap in their droves, with one user writing: "Happy Anniversary to this beautiful couple", as another wrote: "All the best to the leading by example couple!"

Since tying the knot six years ago, the royal couple have conducted numerous international tours from the likes of Canada to India and the Caribbean among others.

Along with the overseas duties William and Kate have taken on in support of The Queen and on behalf of the British government, they've had a very busy few years. William quit the RAF in 2013 and the couple have welcomed two children, Prince George and Princess Charlotte in that time.

Duke and Dutchess of Cambridge
The Duke and Duchess of Cambridge on a two-day Paris visit in 2016 Reuters