Meghan Markle could be barred from entering the US if she opts to become a British citizen, according to reports.
Currently the Duchess of Sussex is a dual British and US citizen, as is her young son Archie.
But with the US government stepping up its use of legislation targeting tax "refugees", the pair could one day face issues and a potential diplomatic crisis.
By law all Americans have to pay tax whether they live in the US or not.
The only way to stop this is to renounce citizenship, although there is no indication that Meghan plans to do this in the immediate future.
This could cause a massive headache, however, as the US State Department says renouncing citizenship is considered grounds for denying re-entry to the country, The Telegraph reports.
One person who has renounced US citizenship is Boris Johnson, who was born in New York.
The Tory leadership contender - who was five when he came to the UK - renounced his US citizenship in 2016 after being hit with a large tax bill following the sale of his London home.
Only one other country in the world, Eritrea, taxes citizens even if they live outside the country.
So far this year more than 1,000 people have given up their US nationality.
The law has been more strictly enforced since 2016.
There is a possibility that Archie could be given an exemption because he is a royal, but one expert told The Telegraph he thinks this is unlikely.
Paul Miller, of New York accountancy firm Miller & Company, said: "I highly doubt they would agree to that.
"The US government is greatly in debt. They want every penny they can get."
