The bad blood between Queen Elizabeth II and her granddaughter-in-law, Meghan Markle, can be traced back to 2018, when the American actress was preparing to marry Prince Harry.
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A royal insider told The Sun, 'Meghan had her heart set on this tiara with emeralds in it and Prince Harry hit the roof when they were told it was impossible for her to wear it' on their wedding day.
It's believed the Queen did not want Meghan wearing it because it's origins could be linked back to Russia.
Regardless of the tiara's history, Meghan was furious at Elizabeth.
'There was a very heated exchange that prompted the Queen to speak to Harry,' the insider explained.
'She said: "Meghan cannot have whatever she wants. She gets what tiara she’s given by me."'
The tiara fight lead to Elizabeth being agitated about Meghan's desire to wear a veil, too.
'The message from the Queen was very much Meghan needed to think about how she speaks to staff members and be careful to follow family protocols.'