HRH Princess Estelle Silvia Ewa Mary, Duchess of Östergötland.
The name is not unknown in the Swedish Royal Family. Count Folke Bernadotte's wife was Estelle Manville, a very wealthy American.
Every royal name started out as a non-royal name. It was not until a little princess was given the name Alexandrina Victoria (for her mother, Victoire) that the name Victoria entered the royal baby name book. The Prince Regent gave her the names Alexandrina (for her godfather Alexander II) and and Victoria because he did not want her to be called Elizabeth or Charlotte. The Prince Regent did not think the Kent princess would be a queen.