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.
Richard Bacon started his career on BBC Radio Nottingham before going on to present on national television and radio including the Big Breakfast, Top of the Pops and Radio 5 live.
He then broke into the US media scene and has a show on Fox TV and lives in Los Angeles.
Juliet Bacon said in her Instagram post she had been visiting him in intensive care for a week.
Radio Nottingham presenter Dean Jackson helped launch his career by giving him his first job on air and has kept in touch with the family.
“He is being kept in the coma to get more oxygen into his system but they are hoping to reduce the sedative soon so hopefully there will be good news”, he said.