All Creatures Great and Small (1978) : 7x7

Buffoon Stewie Brannen, an old friend of Siegfried's, has invited the distinguished Professor Norton to a black tie dinner, and prevails upon Siegfried to host it at Skeldale -- and lend him a dinner suit. But disaster looms when Siegfried and Stewie are called out for a calving, in full evening dress, and James has to hold the fort with an irascible Mrs. Alton.