Armstrong was/is a radio and TV minister, not so much a conventional
televangelist but a commentator and preacher, very strait-laced,
never-crack-a-smile type of guy. In the 60s, he was the chief public
spokesman for the Worldwide Church of God (started in the 1930s by his
father, Herbert Armstrong, as the Radio Church of God). This church was
(and still is) considered a cult group by most conventional Christian
churches - it never has had a big following but had enormous
financial resources and was best known through its radio and TV
programs in every English-speaking country... Garner "Ted" broke with his
father in the late 1970s and started his own ministry, and as of 1993
he was still listed in the Neilsen ratings as one of the top 20
most-popular television ministers...
I just always assumed that Viv had heard him on radio or TV somewhere
and it tickled his funnybone to imagine such an utterly humorless man
indulging in a little jazzy scat singing...