Picture from 2005 shows Lady Sonia McMahon with Crown Prince Frederik of Denmark a Cancer Research Foundation Dinner in Sydney. McMahon, the glamorous widow of former Australian prime minister Sir William McMahon and mother of Hollywood-based actor Julian, has died in Sydney, a hospital spokesman said Saturday.(AFP/Pool/File/Patrick Riviere)AFP – Lady Sonia McMahon, the glamorous widow of former Australian prime minister Sir William McMahon and mother of Hollywood-based actor Julian, has died in Sydney, a hospital spokesman said Saturday.