The Queen reportedly decided to make Camilla the next queen five years ago.
In a statement marking her 70th year on the throne yesterday, the monarch revealed she wants Camilla to take on the title of Queen Consort when Charles becomes King.
The move was dubbed "extraordinary" by some experts, who thought she would follow the trend with the title of "Princess Consort".
But this is not the first time Her Majesty gave her permission for the duchess to take the role, according to one senior royal source.
The source claims the Queen gave her blessing five years ago for Charles to call his wife "Queen Camila" at his coronation.
After the Queen's announcement over the weekend, it was also reported that Camilla will receive the Queen Mother's priceless 1937 crown when she ascends to the position.
The crown famously features the 105-carat Koh-i-Noor diamond, which originated in India, in a platinum mount.
The blessings piled on Camila this week are a world away from the complex relationship between her and the Queen in earlier years.
Once referring to her as "that wicked woman", Her Majesty disliked Camilla for what she saw as meddling in Prince Charles's marriage with the late Princess Diana.
But in recent years, the Queen's contempt cooled and insiders say she has been actively preparing the Duchess for her new role.
Speaking of Charles's plan to call his wife "Queen Camilla", the source explained: ‘This is something that has been on the Prince of Wales’ mind for some time, but the timing had to be right.
"There was a nervousness, they wanted to get it right.
‘It’s been a done deal for some time, but the question has been how best to execute it. You are not going to please everyone.'
Another senior royal source reportedly said the Queen felt Camilla ‘deserved’ to get the proper title that ‘comes with the job’.
They said the Duchess has never tried to 'overshadow' and always played a 'supportive role' but she has also 'carved a role out for herself'.
Other changes to the coronation plans have also been made, with officials reportedly shortening it from usual three-hour long event to ‘better reflect the times’ and it will be more reflective of religious, cultural and ethnic diversities.
After the Queen's historic announcement this weekend, Charles issued his own statement stating his sheer gratitude to his mother for her support, adding: 'We are deeply conscious of the honour represented by my mother’s wish.'
He also paid tribute to the Queen's Platinum Jubilee this year, by saying her ‘devotion to the welfare of all her people inspires still greater admiration with each passing year’.
