Actor Jason Isaacs has paid tribute to his "genius" Harry Potter co-star Sir Michael Gambon, who has died at the age of 82. Isaacs said Gambon, who played Professor Albus Dumbledore in six films, "made fun of himself, made fun of acting and made fun of everything, all the time". Screenwriter David Hare added Gambon was "known to be one of the great actors of the day". Report by Brooksl. Like us on Facebook at http://www.facebook.com/itn and follow us on Twitter at http://twitter.com/itn