EastEnders’ Jim Branning is thought to have suffered a second stroke.
Actor John Bardon, 68, was admitted to a The Lister Hospital, London, on Friday night.
In June 2007, he suffered a massive stroke, which caused him to lose mobility.
His character Jim is in a nursing home in the BBC soap but returns to Albert Square for his birthday.
He will be seen on screen in the one-off special tonight.