What is the fine-grained topic of the following text: In the supporting roles are Conal Coad as Timur, John Longmuir, Graeme Macfarlane and Luke Gabbedy as Pong, Pang and Ping, David Lewis as the Emperor and Gennadi Dubinsky as the Mandarin with the Australian Opera and Ballet Orchestra and Opera Australia Chorus. Only return the topic.
Supporting cast and orchestra of an Opera Australia production