TV entrepreneur Duncan Bannatyne has suffered a suspected heart attack while working in his office, a company spokeswoman says.
The wealthy star of Dragons' Den was being treated at Darlington Memorial Hospital after falling ill at the headquarters of his gym company in the town.
A spokeswoman for the Bannatyne Group said: "Everyone at the company is very concerned and upset, but we know that Duncan is a very strong person and we are confident he will make a full recovery.
"Everyone wishes him well. We'd like to thank the quick and professional actions of the paramedics who attended to Duncan and thank the staff at the Memorial Hospital for his ongoing care."
Bannatyne, who lives on the exclusive Wynyard estate in the countryside north west of Middlesbrough, was born in Clydebank, Scotland and was raised in what he describes as "relatively modest circumstances".