The scientist, who was portrayed by Eddie Redmayne in acclaimed film The Theory of Everything, was due to make a speech at the fabled music event in Somerset, England on Friday (26Jun15), but he pulled out at the last minute.

A spokesperson for Hawking tells the decision to scrap the appearance was made for "personal reasons".

The cancellation comes just hours after rapper Azealia Banks also exited the line-up, axing her Saturday (27Jun15) slot.

Other non-music events at this year's (15) festival include a talk by Welsh singer Charlotte Church and Russian punk rockers-turned-activists Pussy Riot, which took place on Friday morning, and a planned appearance by the Dalai Lama on Sunday (28Jun15).