Why is Meghan Markle suing the Mail On Sunday?

Meghan Markle is suing the Mail On Sunday after it published extracts of a letter she wrote to her father a few months after her wedding to Prince Harry. The duchess saod the letter was private, but the newspaper claims it can't have been considered private because her friends told People magazine about it in an interview they did. The matter is going to a full trial in the UK next year and the duchess will appear via video link from her home in California. Yahoo UK will bring all the details of the case.