The source also revealed the former Suits star has her mother, Doria Ragland, by her side.
Doria arrived in London this week, and Meghan's father, Thomas Markle, is expected to arrive by the weekend.
"Doria will be here to help Meghan relax in the last days before she becomes a [royal]," the source says, adding that one of Meghan's closest pals, Jessica Mulroney, will arrive next week to "help Meghan out with last-minute touches ahead of her big day."
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