Justified and Ancient was written and produced by the British music/performance art/culture-jamming group The KLF, who were inspired by the mock-conspiracy-theory, quasi-occult, “high weirdness” movement more-or-less started by the underground classic novel The Illuminatus Trilogy.
Basically, they thought it would be hilarious to have country legend Tammy Wynette star in a pop-music video based on those themes, and they made it happen.