After starring in the series "The Organisation" (1971), he co-starred in the London Weekend Television situation comedy "Two's Company" which debuted in 1975. Sinden was cast in the role of an English butler, Robert, to Elaine Stritch's American character, Dorothy. Much of the humour derived from the culture clashes between Robert's very stiff-upper-lip Britishness and Dorothy's devil-may-care New York view on life. "Two's Company" was well received in Britain and ran for four seasons until 1979. The programme was nominated for a 'Best Situation Comedy' BAFTA in 1977. Stritch and Sinden also sang the theme tune for the opening credits to the programme, which received a BAFTA nomination. They each received a BAFTA nomination in 1979 for 'Best Light Entertainment Performance' and the show received two additional BAFTA nominations that year.