Sir Bruce Forsyth has spent five nights in intensive care after developing a severe chest infection.
The 89-year-old's manager confirmed to the BBC Sir Bruce had been in hospital since Sunday.
It is not yet known when he will be released from hospital, but it is possible he could be returning home on Friday.
A friend of Sir Bruce has told the Daily Mail the presenter remains "in great spirits".
In 2015, the presenter underwent surgery after suffering two aneurysms, which were discovered when tests were carried out following a fall at his Surrey home.
Sir Bruce left Strictly Come Dancing in 2014, having presented it since the first series, but his manager denied reports in October that he had retired from the entertainment industry.
Ian Wilson said at the time that Sir Bruce was "recuperating from various health issues", adding: "His sole focus at the moment is to continue getting better and he has made no formal or informal decision about retiring from showbusiness."
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