While both Roy Clark and Lawrence Welk were prominent figures in the world of country and popular music, their musical styles and approaches were quite different. Clark was known for his virtuosic banjo playing, comedic stage presence, and blend of country, pop, and rock influences. Welk, on the other hand, focused on a more traditional, polished approach to music with a strong emphasis on big band arrangements.
There's no evidence of them ever collaborating or appearing together on a show.