A spokesman for Madonna has previously said that Malawi's President has a "grudge" after her sister Anjimile Oponyo was sacked as the head of her charitable foundation Raising Malawi.
Ms Oponyo was sacked due to "concerns about mismanagement of $3.8m", said Trevor Neilson, whose Global Philanthropy Group manages Madonna's projects in Malawi.
The allegations have been denied by Ms Oponyo and the President Joyce Banda's office has dismissed the claim.
More top news
The Duke and Duchess of Cambridge met young people who have battled mental health issues on Saturday.
Former Chancellor Lord Geoffrey Howe was Margaret Thatcher's longest-serving Cabinet minister, also taking on the role of Foreign Secretary.
Lord Geoffrey Howe is known by many for his resignation speech which was seen as the catalyst which destroyed Margaret Thatcher.