According to The Sun, Grantham has been visited in hospital by close friends in the industry.
The character was apparently killed off in 1989 but Grantham made a shock return to Albert Square in 2003.
The 71-year-old, famous for playing “Dirty” Den Watts in the BBC soap, has returned to the UK from Bulgaria where he had been living and is being closely monitored by doctors.
Grantham shot to fame while playing Watts in EastEnders, originally from 1985 to 1989.