Teri Garr?

Obviously, "The Big T.N.T. Show" is not on her imdb page.

I have a feeling that the still you have (as is much of the footage of dancers in the opening sequences of T.N.T.) is really recycled from the previous year's T.A.M.I. show.

T.N.T. seems to be a lower-budget affair, with less use of background dancers (since their musical acts were less dance-oriented).