Camilla is "deeply unhappy", according to insiders, as the Queen is understood to face a constant battle with King Charles.
Despite being diagnosed with a form of cancer earlier this year, the monarch continues to perform a packed schedule of royal engagements.
This includes an upcoming gruelling overseas tour to Australia, which is being planned for October.
Earlier this week, King Charles, 75, began his summer holiday at Balmoral Castle in Scotland for a well-deserved break.
Camilla is 'deeply unhappy' as Queen faces constant battle with King CharlesGettyHe took part in a traditional Balmoral welcoming ceremony on Monday.
However, the following day King Charles flew hundreds of miles for a visit to Southport, where the vile murder of three young children attending a Taylor Swift-themed dance class occurred.
The King then travelled to London the next day for a private meeting with the bereaved families of the three children.
No details were released of the meeting, except that it occurred at the King’s London home, Clarence House.
King Charles visited Southport earlier this week
PA
He is thought to have then received cancer treatment in London and helicoptered back to Balmoral on Thursday.
A friend of Queen Camilla's claimed she is "deeply unhappy" with the King's packed work schedule and wants him to focus on his recovery.
They told The Daily Beast: "Camilla would have been deeply unhappy that having only begun his holiday on Monday, he broke it off on Tuesday to do an incredibly intense engagement.
"Of course, she understands it was very important and there is no way she would try to tell Charles what to do, but it seems to be extraordinary timing.
Balmoral Castle is located in Aberdeenshire, ScotlandGettyLATEST ROYAL NEWS:
King Charles has been having treatment for a undisclosed form of cancer Getty"She wants him to slow down, she is afraid he is working too hard, and that’s before you even get to the Australia tour."
Camilla has voiced her concern publicly telling well-wishers she wants Charles to "behave" and "slow down".
Another friend said: "She has been trying to encourage him to slow down. Of course, he wants to keep cracking on, but she is afraid that doing too much could set him back."
GB News has approached Buckingham Palace for comment.
