Dead, Alex Giannini, who appeared in Elizabeth: The Golden Age and Miss Monday, and featured in TV shows such as The Bill and Dalziel and Pascoe.
Agents Felix de Wolfe added: “An incredible life force has left the building.”
Stephanie Sirr, chief executive of Nottingham Playhouse tweeted: “Shocking, terrible news. A lovely man with incredible zest for life. A great performer.”
The performance on Friday evening was cancelled about an hour before the curtain was due to rise.
David Bloom, of the Chichester Festival Theatre production company, said: “There has been a company bereavement and so the performance tonight has had to be cancelled.”
All remaining performances would go ahead as scheduled, the theatre said.
The theatre, wrote on Facebook: “Thank you to everyone who was affected by last night’s cancellation, for your patience and understanding.”
Alex Giannini died at age 52 on October 2, 2015.