She had not been seen in public since and was recently forced to miss several engagements, including a Centrepoint Royal Albert Hall fundraiser and the British Military Tournament.

BBC: Duchess of Cambridge attends BBC sport awards

Proceeds from the concert will go to a number of charities that were supported by the princess during her life, and to two of the princes' own charities, Centrepoint and Sentebale.

BBC: The princes say they want both sides of the family to attend

Meantime, to forestall talk about the cost of keeping the Arthur Andersen team in the country for almost a year, the group was moved from the Sheraton to the Centrepoint, a marginally more modest hotel.

CNN: INTELLIGENCE