British media as saying that Professor Stephen Hawking has died, says their family spokesperson.
An update by the BBC also said that Prof Hawking has died at the age of 76.
Prof Hawking was a theoretical physicist, cosmologist, author, and Director of Research at the Centre for Theoretical Cosmology within the University of Cambridge.
He was known for his work on gravitational singularity theorems in the framework of general relativity and the theoretical prediction that black holes emit radiation.
His books A Brief History of Time, The Universe in a Nutshell and The Grand Design have been bestsellers