Mr. Guest was starring the Melbourne version of the hit musical Wicked as the Wizard of Oz at the time of his death. He was well known to Australian theatre audiences as the former star of The Phantom of the Opera and Les Miserables. He was the world's longest-serving Phantom, having played the role a record 2,289 times over seven years. Mr. Guest's career took him many places before he landed in Australia. He was born July 17, 1950, in Birmingham, England. He began his performing career as a pop singer, climbing the New Zealand radio charts and starring on many television shows. He was voted the 1978 New Zealand "Professional Performer of the Year." Soon after, he moved to the United States where he sang in various resort cities such as Las Vegas throughout the 1980s.

He moved to Australia to take the role of Jean Valjean in Les Miz and ended up playing the part for three and a half years. He then moved on to Phantom. Other Australian theatre credits included The Sound of Music, Footloose, Jolson and The Music Man.