The singer, who died of AIDS-related pneumonia in 1991, sat down with a German film crew in Munich in 1982 for the Tv chat over a pint of beer and a cigarette - and mused about his own band's 20th anniversary, which he didn't live to see.
Mercury says, "It would be nice if people still buy our records (in 10 years' time)."
During the eight-minute interview, which features as an added extra on the Dvd alongside a backstage chat with his bandmates Roger Taylor and Brian May before their landmark gig at the U.K.'s Milton Keynes Bowl on Queen's Hot Space Tour, Freddie also opens up about the temptation of becoming a diva rock star behind the scenes.
He says, "Egos can run wild. You have to keep one foot on the ground. It's easy to say, 'I'm a big rock star; I want everything.'"
In the lost interview, Mercury also talks about Queen's "visual theatrics" onstage and the state of the music industry in 1982.