How does one ensure good relations amongst dinner guests, when Prince Phillip is present?

I am hosting a dinner party, and one of my guests is Prince Phillip. Bearing in mind that the guest list includes a Chinese diplomat, an African tribal chief, an Indian surgeon, an Arab shiek, and a Ladyboy from Bangkok, how do I ensure that Phil does not place his royal foot in it and make some comment about "bones in noses" or some other comment which may offend my esteemed guests?