Royal commentator Camilla Tominey explained to The Express: “Aides had agonised over whether Kate should attend Thursday’s engagement but she will not be present.
“While William always wanted his wife of 10 years to be by his side, there were concerns that Harry might feel ‘outflanked’ by the Cambridges if they were there together and he was on his own.”
Prince Harry was last in the UK for his grandfather Prince Philip's funeral in April.
As Meghan was heavily pregnant with baby Lilibet, she didn't fly out with her husband but the royal rift seemed to have mended when Harry was spotted walking with his brother and sister-in-law.
This was the first in-person reunion between the brothers since the explosive Oprah interview where Harry and Meghan spoke about the lack of support they received from their royal relatives and Kate was expected to play "peacekeeper" for William and Harry ahead of the event as well.
"Being so close to her own siblings, Pippa and James, and having witnessed firsthand the special bond between William and Harry, she has found the whole situation difficult and upsetting," a source told the Telegraph UK.
WATCH BELOW: Prince Harry speaks to sister-in-law Kate Middleton at Prince Philip's funeral. Post continues after video...
In 2017, Prince William, Duchess Catherine and Prince Harry joined forces to visit The Sunken Garden that was transformed into a White Garden to mark the 20 year anniversary of Diana's death.
Before Meghan joined the family, the three had a close relationship with Harry speaking fondly of Kate.
"To have a big sister is very, very nice... She's a fantastic girl, she really is, my brother is very lucky," the redheaded royal once revealed of the Duchess.