The world-famous scientist, whose life story was recently turned into an Oscar-winning film "The Theory of Everything", will appear at the festival's Kidz Field, reported BBC online.
A message on the festival's website said he would make "a special guest appearance" in the field which is aimed at children aged 12 and under.
Magician Dynamo was also announced for the festival, which is held in June.
Veteran rockers The Who were named last week as the headline act for the Pyramid Stage on Sunday night.
Other big acts confirmed for the sold-out festival include Foo Fighters, Kanye West and Florence And The Machine.
He also appeared in a Comic Relief sketch with David Walliams and Catherine Tate.