During the moving interview -- which took place before the anniversary of Michael's death -- a visibly upset Katherine claims, "Not a day goes by that I don't think about my son."
The clip was shot by the same website hawking Katherine's new book "Never Can Say Goodbye" -- and according to our source, the footage is all part of a larger documentary on Jackson's life.
As for who's behind the whole project -- we're told it's an equal partnership between Katherine and Howard Mann -- the same guy who co-wrote her book.
