The Duchess will be attending with her daughter as a special guest of charity founder, philanthropist John Caudwell.
In an additional twist, the charity has also confirmed that singer, Peter André, is scheduled to perform for the 1000 guests on Thursday 20th May.
National charity, Caudwell Children, stages the ultra-glamorous Butterfly Ball in the Capital every May, and a host of A-List stars turn out to support the charity which provides donations of specialist equipment, treatment and therapy for sick and disabled children living in the UK.
Caudwell Children CEO, Trudi Beswick, commented on the forthcoming event: “We are delighted that the Duchess and Princess Beatrice are joining us for the evening. They have learnt about our work over the last 12 months and are now attending to show their continued support for the Charity.”