Leading scientist Stephen Hawking's condition has "improved" after being admitted to hospital with chest problems, Cambridge University says.
His employers said Professor Hawking was undergoing tests on Monday at Addenbrooke's Hospital, Cambridge.
A university spokesman said the 67-year-old, who has motor neurone disease, was now "comfortable".
Prof Hawking, author of A Brief History of Time, has worked at Cambridge University for more than 30 years.
The world-famous physicist, who is wheelchair-bound and speaks with the aid of a voice synthesiser, had flown to the US at the end of February to the California Institute of Technology where he is a visiting scholar.
But he had not been well for some weeks and called off an appearance at Arizona State University on 6 April because of his illness.
He was flown back to the UK on Saturday and was admitted to Addenbrooke's on Monday after being seen by a doctor.
-Article continues (off site), courtesy BBC News.
