Television and radio presenter Richard Bacon is in a medically induced coma after becoming critically ill with suspected pneumonia.
He was taken to hospital eight days ago after becoming unwell on a flight from to Britain from the United States.
The former Blue Peter presenter had been well enough to post photos of himself on social media.
But his sister confirmed his condition worsened and he has had a tracheotomy to help him breathe.
The presenter posted a picture on Twitter of himself in hospital on 5 July.