Richard Bacon “would have died” if doctors had not put him into an induced coma when he was struck by a mystery illness on a flight to the UK.
The former Blue Peter presenter has spoken about the “most shocking moment” of his life in a candid interview following his release from Lewisham University Hospital, in south London.
The 42-year-old fell ill while flying to Britain from the US and was taken off the plane in a wheelchair.
He was admitted to hospital two weeks ago and placed in a medically-induced coma.
Bacon said during the first two nights in hospital "the infection was winning and my lungs were losing" and he has since found out he came "quite close to death" during this time.
"I have had a couple of moments of feeling slightly haunted by it," he said.
Bacon said doctors will "never know" what he was struck by but added: "I'm fixed, it's gone."
He told the Radio 4’s Broadcasting House: "I must have been injected 250 times in the last two weeks... because they didn't know what it was."
He added it was "the most shocking moment of my life"
Bacon thought he would have one night in hospital but the consultant told him: "'I need to put you into an induced coma so that we can control your breathing and if I don't do that you're probably going to die.'
"To start with it was profoundly shocking and then I was immediately at peace with it because he'd taken the decision away...
"Within minutes it's a new reality."
Bacon, who has been living in the US, told the Radio 4 show that he had visited the gym twice a day in Los Angeles and was in the midst of the “healthiest year of his life”.
He told how he began feeling unwell during the flight, saying: "I started to feel very, very cold and slightly hallucinogenic...
"I felt like I was sitting in a field in winter and I was rocking back and forth. I was in such a state that when we landed after 10 hours that they had to get me off the plane in a wheelchair."
But Bacon said: "This is where being in good shape worked against me. I think because I knew I had worked hard this year I thought, 'I'll be alright' so I didn't go straight to A&E which was a mistake."
He said: "I was short of breath and what I should have done, and what I would urge anyone to do if ever short of breath through reasons they can't ascertain, is you go straight to A&E.
"The next morning I went to A&E and even then I didn't treat it very urgently. I just did a walk-in."