Queen Camilla may step in for King Charles at the D-Day 80th anniversary ceremony in France if he is too ill to attend, the Mail on Sunday can reveal.

Aides have not yet ruled out the possibility that the King, who has cancer, may be well enough to travel to Normandy on June 6. But preparations are being made for the Queen to go in his place.

It would see the Queen front and centre with US President Joe Biden, Canadian Premier Justin Trudeau and French President Emmanuel Macron, who are likely to attend the official international ceremony on Omaha Beach in Normandy, which was targeted by Allied forces in the invasion of Nazi-occupied France.

The King is understood to be keen to attend the D-Day 80th anniversary, which will be one of the last with living veterans, but he may have to concede he is not well enough to make the trip. 

And his doctors may advise against it.

Queen Camilla may step in for King Charles at the D-Day 80th anniversary ceremony in France if he is too ill to attend. Pictured: Camilla at the 75th D-Day commemorations in 2019

The King is understood to be keen to attend the D-Day 80th anniversary, which will be one of the last with living veterans. Pictured: Charles, then prince, at the VE Day Commemorations in Lyon in 2018

The occasion is also of personal significance to Camilla, whose father, the late Major Bruce Shand was a decorated war hero who served in the Second World War.

Prince William, who holds several forces roles and completed seven-and-a-half years of full-time military service, will likely also participate in the commemorations, but no specific plans have been confirmed.

The Queen has stood in for several events since the King revealed his cancer diagnosis earlier this year.

Sources said the monarch was 'very proud of her' and believes she has been doing 'a wonderful job'.

Last week Camilla led her most high-profile public engagement yet on Charles's behalf at the Maundy service at Worcester Cathedral, becoming the first consort to perform the ancient tradition.

Last week Camilla led her most high-profile public engagement yet on Charles's behalf at the Maundy service at Worcester Cathedral, becoming the first consort to perform the ancient tradition 

READ MORE: How the Royal Family's Easter will be very different this year: From a 'smaller than usual' guest list for the sake of King Charles to Kate's absence amid her cancer battle

King Charles is expected to attend the traditional Easter Mattins service on Sunday at St George's Chapel, Windsor, which will be the first time he has been seen walking in public since January.

Both Charles and Camilla will then enjoy some time off after Easter, with the King expected to return to Highgrove, his country home in Gloucestershire, which friends say is his 'sanctuary'.

Looking ahead, royal schedules are understandably fluid depending on the King's health.

'We plan for the best but prepare for changing situations,' a palace aide said.

The King is then expected to 'gradually dial up' his diary towards the summer, with plans to take part in larger outdoor gatherings. 

It was also reported last week that Charles 'hopes' to attend Trooping the Colour in some form on June 15.