King Charles and Queen Camilla attend Sunday church service as the monarch prepares to return to public-facing duties and Harry announces return to Britain for Invictus service

King Charles and Queen Camilla attended a Sunday Church service as the monarch prepares to return to public-facing duties and Harry announced a return to Britain.

The couple were pictured arriving at Crathie Church in Aberdeenshire this morning following Friday's announcement that he is on the mend after months of cancer treatment.

The recovering King and Camilla arrived in the late Queen's beloved Balmoral estate - their first visit to Scotland since his diagnosis - on April 11 for some R&R and to celebrate their 19th wedding anniversary. 

It comes as Prince Harry is set to return to Britain in just a few days for the Invictus Games 10th anniversary in his first visit since Kate Middleton revealed her cancer diagnosis. 

An Invictus Games spokesperson confirmed the Duke of Sussex will attend the Service of Thanksgiving at St Paul's Cathedral on Wednesday May 8, but it is yet unclear whether his wife Meghan Markle will be joining him.  

At the Service of Thanksgiving at St Paul's Cathedral, Harry is expected to provide a reading at the event, marking a decade since the games were founded as a sporting event for injured and sick military personnel and veterans. 

Actor Damian Lewis is also expected to recite the Invictus poem at St Paul's for the anniversary of the games for injured servicemen and women.

It comes as the Duke is embroiled in a legal row about his taxpayer-funded personal security when he visits Britain.

The visit is the first time the Duke of Sussex has been in the UK since his last 26-hour trip in February, after his father King Charles announced his cancer diagnosis.

Royal experts say it is 'unlikely' that Harry will meet with the Princess of Wales, who disclosed her own battle with the disease in a video message to the nation last month.

Tom Bower told MailOnline: 'I'm sure he won't see Kate. But to reassert his royalty and his titles to enhance his brand, he will make a huge effort to be seen visiting his father, the King. I would be surprised if Meghan came.

Royal commentator, Richard Fitzwilliams added: 'Katherine is undergoing preventative chemotherapy treatment and given how deep the rift is, to me it seems unlikely.

'The only hope of reconciliation is that it would happen privately and we wouldn't know.'

However, Mr Fitzwilliams pointed out that a serious illness can sometimes be a 'gamechanger' in familial relationships. 

A statement published on the Invictus Games' social media reads: 'The Invictus Games Foundation will celebrate 10 years of changing lives and saving lives with a 'Service of Thanksgiving' at St Paul's Cathedral on May 8th.

'We will be joined by our Patron, Prince Harry, the Duke of Sussex, actor Damian Lewis and members of the worldwide Invictus Community to mark the occasion.' 

However, Meghan is not mentioned. As the event is just two days after their son Archie turns five, it is likely she will stay at home.

The pair live in Montecito, California with their two children, Archie, four, and Princess Lilibet, two.

In her statement, the Princess of Wales revealed she had been diagnosed with cancer after 'planned abdominal surgery' in January.

The Duke and Duchess of Sussex were understood to have made contact with the Prince and Princess of Wales 'privately' after Kate announced her cancer diagnosis.