[Warren]

From the above link:

Queen Elizabeth hosts dinner for the Aga Khan at Buckingham Palace

The Queen is hosting a dinner party in honour of the Aga Khan IV.
Senior members of the Royal Family will attend the Buckingham Palace dinner on Monday for the long-term friend of the Queen.
He is also the Imam of the world's 15 million Shia Ismaili Muslims and a direct descendant of the Prophet Muhammad.
Last year he celebrated the 50th anniversary of his succession to the title held by his grandfather.
The Aga Khan is coming to the end of a seven-day visit to the UK held to mark the milestone.

Among the guests pictured were Prince Amyn Aga Khan, Princess Yasmin Aga Khan, and Prince Hussain Aga Khan and his wife Princess Khalyia.