He said: "They do things how they want to adapt them".
Markle joined her husband-to-be and Britain's other senior royals including Harry's father, Prince Charles, and his elder brother Prince William and his wife Catherine at London's Westminster Abbey for the Commonwealth service on Monday.
The future duchess is feeling the pressure of her upcoming nuptials, and dealing with it the only way an true LA native knows how... through twice-daily meditation practice.
They were greeted by thousands of people outside the central London Abbey after the service, including hundreds of school children invited by the family and the Prime Minister.
In her Commonwealth Day message, which is printed in the event's order of service, the Queen highlighted the diversity of Commonwealth nations and the connection between its peoples.
Between that and her strong hat game, Markle is basically a royal already.
The insider told the Star on Sunday newspaper: "The royals understand why Meghan might prefer to have her mother, but it's not exactly traditional to have a woman walk a bride down the aisle".
Markle's baptism wasn't a prenuptial requirement, however; she was baptized and confirmed out of respect to Queen Elizabeth II, who is head of the Church of England.
For her part, Duchess of Cambridge Kate Middleton didn't attend any events with her grandmother-in-law before marrying Prince William back in 2011.
She also learned what to do if she is kidnapped, subjected to gunfire and intensely interrogated.