Cancer-stricken King Charles grins as Queen Camilla gives a friendly wave as they are spotted together driving to Sunday Service at Crathie Kirk

Cancer-stricken King Charles beamed this morning while Queen Camilla gave a friendly wave to well-wishers as they drove to the Sunday Service at Crathie Kirk.

The couple had arrived on the late Queen's beloved Balmoral estate in Aberdeenshire on Thursday for some R&R and to celebrate their 19th wedding anniversary. 

The King's arrival in Scotland marked the first visit to the country since he revealed his cancer diagnosis in February sending shockwaves around the globe. 

Charles has largely stepped back from his public facing duties since revealing his illness, however, has continued to read his daily red boxes and have his weekly audience with the Prime Minister. 

Providing a much needed boost to the British public, who are still reeling from the Princess of Wales' cancer diagnosis last month, the King has been seen out and about.  

Cancer-stricken King Charles beamed this morning while Queen Camilla gave a friendly wave to well-wishers as they drove to the Sunday Service at Crathie Kirk

Cancer-stricken King Charles beamed this morning while Queen Camilla gave a friendly wave to well-wishers as they drove to the Sunday Service at Crathie Kirk

He made an appearance alongside other senior royals at the Easter Sunday service at Sandringham, shaking hands and chatting to those royal fans who had lined the nearby road.

After arriving in Aberdeen Airport from RAF Northolt in north-west London on Thursday evening, Charles and Camilla travelled to Birkenhall.

Birkenhall was the home of the late Queen Mother on the Balmoral Estate and later came into the King's possession.

It is seven miles away from the castle and is where the King and Queen spent their honeymoon after tying the knot on April 11 2005. 

The monarch, as with his daughter-in-law Kate, has not disclosed what type of cancer he is fighting.

It is unclear if during he has completed his care or is convalescing in-between treatments as he visits the Scottish highlands.

Charles was previously advised by doctors to avoid any large-scale public events and visits to protect his health during a crucial stage in his treatment.

Despite this, he has remained within the public eye and it is understood that he will 'ramp up' his schedule in the coming weeks. 

Charles and Camilla, celebrate their 15th wedding anniversary, at Birkhall, their home on the Balmoral Estate, on April 8, 2020

Looking up towards the house which dates from 1715, across the garden of Birkhall, on the Balmoral Estate in Aberdeenshire

The King and Queen have been pictured arriving in Aberdeen for a romantic break at their beloved Highland retreat as the couple celebrate 19 years of marriage

One insider previously told the Mail: 'The idea of a monarch cloistered away just wouldn't wash nowadays and will only create damaging speculation about His Majesty's health.' 

A source added last month: 'While it is too early to confirm things – and, of course, it is relatively early in His Majesty's treatment cycle – the patient is positive, the doctors are optimistic and the treatments are incredibly sophisticated.' 

Before potentially taking more on in the public eye, however, Charles has retreated to the remote estate in the heart of the Cairngorms National Park.

Queen Elizabeth used to spend most of her summers on the estate, horse riding or taking long strolls.

It is understood Charles previously used the Birkhall retreat to recover from a corrective procedure after being diagnosed with an enlarged prostate while he was staying there. 

He also chose it as his honeymoon destination with Camilla after their wedding 19 years ago, and they spent New Year's Day there last year.

The monarch is said to be 'so optimistic' about his treatment that he hopes to attend Royal Ascot this summer, as well as some of the garden parties at Buckingham Palace that honour community and military heroes.

The Balmoral estate has been home to the Royal Family for more than a century.

Earlier this month it was revealed that the King will open Balmoral's interior to the public for the first time from July 1. 

Buckingham Palace will also be open to for public viewing.