In the 1970s, Duncan performed duets with Janie Fricke, many of which were highly successful. Their songs "Stranger" and "Thinking of a Rendezvous" (both 1976), "It Couldn't Have Been Any Better" (1977), and "Come A Little Bit Closer" (1978, a remake of the song first made popular by Jay and the Americans) were the most successful. In fact, "Thinking of a Rendezvous" and "It Couldn't Have Been Any Better" both went to No. 1number one on the "Billboard" Hot Country Singles chart, as did Duncan's solo 1978 single "She Can Put Her Shoes Under My Bed Anytime".