The Dragons' Den entrepreneur, who runs The Bannatyne Group health club and hotel chain, was taken to the emergency room in Darlington, England over fears he had suffered a heart attack.
He has since taken to Twitter.com to tell followers he is recovering well and hopes to be discharged on Tuesday (02Oct12).
Bannatyne writes, "In hospital attached to a few wires, feeling tired but am sure I will be discharged... Fit and well (fit as a pensioner can be anyway)... Today was my first trip inside an ambulance and with siren wailing. Hope it is the last... Just waiting for docters (sic) rounds but am sure I will get all clear to go home soon."
Bannatyne's TV co-star Theo Paphitis also tweeted after checking in with his pal, writing, "Managed to make contact with Duncan Bannatyne and he is well, undergoing tests. Does not think (he suffered a) heart attack!"
Bannatyne has been a regular on entrepreneurial show Dragons' Den since the programme launched in 2005.