The Duchess of Sussex could be barred from re-entering the US in the future if she chooses to renounce her citizenship.
The US government has started enforcing provisions of 1986 legislation allowing the country to exclude tax "refugees" - Americans who drop their citizenship to avoid paying US tax on earnings they make overseas.
According to the State Department, a small number of former Americans have already been barred from re-entering, and the move could present a dilemma for the Duchess and her son Archie (a dual US-UK citizen) if they choose to become solely British citizens.
A spokesman for the State Department confirmed that renouncing US citizenship for tax purposes were grounds for denying re-entry.
The United States taxes its citizens irrespective of where they live. Anybody born in the US is classified as a US citizen until they renounce their nationality.