But, as a video that resurfaced after news of the engagement broke shows, Ms Markle may need to brush up on her Britishness quotient.
In July 2016 - when she first started dating Prince Harry - the actor agreed to participate in a fun "Britishness" quiz for British show Dave while promoting Suits.
As Ms Markle prepares for life as a British Royal and studies up on British history and culture in preparation for her citizenship test, the hilarious video has suddenly gone viral again.
The video has the California native identify the national animals for England, Scotland and Wales (trust us when we say the answers will surprise you). She also translates popular British slang into "Americanisms" - some more successfully than others.
Watch Meghan Markle take a 'Britishness' quiz below:
Even though she fails the quiz quite miserably, it's clear the actor is having lots of fun and making the Internet smile.
"The Queen would be disappointed," jokes one person. "Girl, you better get on your British slang/history... considering recent developments," jokes another.
"She's lovely! I see why Prince Harry fell in love with her," comments a third. Click for more trending news