Good lord, this  is Terrific:
Tom Seaver. Nancy Seaver. Singing with the Lettermen. Awkwardly joking with Eddy Arnold. Referring in detailed fashion to the World Series just recently won. This aired on NBC’s Kraft Music Hall, November 5, 1969, not three weeks after the Mets commenced their reign as Earth’s baseball champions, only 17 days since Tom and teammates confirmed “You Gotta Have Heart” for Ed Sullivan .
Clearly, humanity had reached its peak.
I’d read of this variety show appearance, but I never dreamed I would see it. Great thanks to my old friend Joe F. for finding it.