Question: Who sang the theme tune to dear john?
Disambiguated questions and answers: question: Who sang the theme tune to the American series, dear john?
Who sang the theme tune to the British series, dear john?
answer: Wendy Talbot
Joan Baxter
question: Who sang the theme tune to the American version of dear john?
Who sang the theme tune to the British version  of dear john?
answer: Wendy Talbot
Joan Baxter
Natural Questions answer: Joan Baxter (from the Wikipedia article "Dear John (UK TV series)")