In August of 1966, Joni Mitchell recorded several songs for a Canadian television series called Mon Pays, Mes Chansons. After the music was recorded in the studio (with David Rea backing her on the second guitar), Mitchell was filmed lip-syncing in color against the mind-boggling natural beauty of Canada, the show being a part of a musical salute to the Canadian Centennial of Confederation.
This isn’t the earliest TV footage that exists of Joni Mitchell, but it’s surely the earliest footage of her performing that’s in color.
I know some people simply can't abide Mitchell, but I'm a fan. The clip, however, notwithstanding its historical value, is kind of unintentionally funny.