LOS ANGELES (AFP) - A US judge on Monday barred defence attorneys for Michael Jacksons doctor, who stands accused of involuntary manslaughter, from calling the singers former physicians as witnesses. The move will hurt the defence team for Conrad Murray, which had hoped the other doctors would help support their theory that the King of Pop who died in June 2009 at age 50 was addicted to drugs. Los Angeles Superior Court judge Michael Pastor agreed to a motion by prosecutors to exclude six of Jacksons former doctors including his long-time dermatologist, Arnold Klein from the list of approved witnesses.