Complementing them on screen are such actors as Helena Bonham Carter , Jim Broadbent , John Cleese , Robbie Coltrane , Warwick Davis , Ralph Fiennes , Michael Gambon , Brendan Gleeson , Richard Griffiths , Richard Harris , John Hurt , Jason Isaacs , Miriam Margolyes , Helen McCrory , Gary Oldman , Alan Rickman , Fiona Shaw , Maggie Smith , Timothy Spall , Imelda Staunton , David Thewlis , Emma Thompson , and Julie Walters , among others.