The opening night of Only Fools and Horses The Musical in Blackpool was halted after an audience member fell ill.
Blackpool's Winter Gardens said Monday's show, based on the long-running BBC TV comedy, was postponed and the Opera House theatre evacuated after a "medical emergency" in the front stalls during the interval.
North West Ambulance Service (NWAS) said it attended the theatre and had taken a man to hospital for further treatment.
The Winter Gardens said its thoughts and well wishes were with the man and his family, and thanked everyone for their patience.
It said ticket holders would receive an email with details of how to transfer to another performance or request a refund.
The musical stars Paul Whitehouse as Grandad and audience members are also reacquainted with much-loved characters including Del Boy Trotter, Rodney and Cassandra, Trigger, Boycie and Marlene.
The show is billed as a celebration of "traditional working class life in London in 1989".
The musical is touring the UK and the Republic of Ireland after a record-breaking four-year run in London's West End.
