Prince Charles has been visiting the Queen at Balmoral more regularly as she continues to suffer mobility problems.
Royal experts said the Prince of Wales' visits are out of concern for the 96-year-old monarch as unscheduled visits are uncommon.
According to the Sun UK, the Queen has been battling with mobility problems for nearly a year.
She was scheduled to travel to Buckingham Palace to appoint a new prime minister for the UK but has been advised against it because of her mobility issues.
Prince Charles has been taking time out of his busy schedule to visit his mother.
Majesty Magazine's Ingrid Seward said: "It's highly unusual for Prince Charles to make these kinds of impromptu visits to see his mother.
"But Charles is a very thoughtful person - and who else can she rely on now Prince Philip has gone?
"Everyone thinks they normally see each other all the time, but they don't."
The Queen's disgraced son Prince Andrew is living with his mother at the Balmoral estate.
The Sun UK reported they said to be locked intense talks over his future after he was involved with infamous sex offender Jeffery Epstein.
A decision will be made next week on whether or not the Queen will travel to Buckingham Palace.
