FROM the circus clown to the character clown like Charlie Chaplin, clown acting has substantially evolved. It has now become an important part of the culture and also a basis in the training of an actor. An eight-lesson course, ''The Foundation of Clown Acting'', organised by the Hong Kong Arts Centre, will show you what a clown is and teach you how to be a good one. The course aims to help students discover their own style as a clown and to understand the relationship between the clown world and performing arts. ''Everybody has his ego which includes his physical body and his mind. A clown is not only a 'fool' in the ordinary sense. In fact, it is the dynamic process of the revelation of the ego of a particular person,'' said course instructor Shu Tang. Contents of the course will include: Fundamental corporal training; training of imagination and emotion; training of energy; the relationship between a person and an object; the expression of power of a clown; the power relationship between two clowns; makeup and formalisation of a clown; improvisation. Actors, dancers and others aged 17 or above are welcome to register for the course. The course will be held at Eric Hotung Studio LB, Hong Kong Arts Centre, 7.45 pm to 10.15 pm, on Thursdays between September 16 and November 4. The fee is $550 ($495 for member).