Sir Donald Alfred Sinden, CBE, is an English stage and film actor. He was born in Plymouth, England, 9 October 1923, son of Alfred Edward Sinden and his wife Mabel Agnes (Fuller). He married actress Diana Mahony . One of their sons, Marc Sinden, is the actor and West End theatre producer. His other son, Jeremy Sinden was also an actor but died in 1996.

A stalwart of the Royal Shakespeare Company he trained as an actor at the Webber Douglas Academy of Dramatic Art and made his first stage appearance at the Brighton Little Theatre (of which he later became President) in January 1941, playing Dudley in George and Margaret. He broke into professional acting after appearing with the Mobile Entertainments Southern Area company in modern comedies for the armed forces during the Second World War.

He subsequently appeared in many British films of the 1950s including The Cruel Sea and Doctor in the House.

Among many notable stage appearance, for the RSC Stratford 1976 season, and then at the Aldwych in 1977, he gave an outstanding comedy performance partnered with Judi Dench as Beatrice and Benedick in John Barton's "British Raj" revival of Much Ado About Nothing.

He reached widespread fame in the long-running London Weekend Television situation comedy Two's Company, in which he played 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. Both Sinden and Stritch performed the title music. He was also to star as Simon Peel in the comedy Never the Twain (1981), in which he played a snooty antiques dealer who had to live next door to Oliver Smallbridge (Windsor Davies), who also ran an antique shop. The pair hated each other, and were thus horrified when they discovered that their son and daughter were to be married - thus meaning they were related. Despite the lack of critical acclaim, this series was to run for 11 years.

He also appeared on radio including Sir Charles Baskerville in the Radio 4 adaptation of the Sherlock Holmes story The Hound of the Baskervilles. Other roles include many in the works of Shakespeare for which he gained plaudits and won numerous awards for his portrayals, a regular appearance as a senior judge (and father-in-law to the title character) in Judge John Deed, and even a guest role in the cult series The Prisoner. He also appeared in the 1978 film The National Health.

He was spoofed mercilessly on Spitting Image (a British satirical television programme in which famous people were usually lampooned by viciously caricatured latex puppets) for his stage actorly delivery and fruity voice (for example, his puppet, sitting in a restaurant, summons a waiter and asks "Do you serve a ham salad?" the waiter replies "Yes, we serve salad to anyone") and was shown fawning to the Queen and requesting a knighthood from her. He did however receive a knighthood in 1997.

Sinden has written two autobiographical volumes, A Touch of the Memoirs (1982) and Laughter in the Second Act (1985), as well as a collection of "epitaphs and final utterances," The Last Word (1994). He was also a leading figure in the fight to launch the Theatre Museum in Covent Garden in the 1980s.

As of 2007, Sir Donald Sinden is currently embarking on a national UK tour, taking in various venues to talk about his life and work.

The son of a country chemist, the British actor Donald Sinden intended to pursue a career in architecture but was spotted in an amateur theatrical production and asked to join a company that entertained the troops during World War II (Sinden was rejected for naval service because of asthma). Following a brief training at drama school, he established himself in theater, particularly as a Shakespearean actor. Having made his film debut in The Cruel Sea (1953), Sinden became a leading man in British films during the 1950s and then moved onto character roles later in his career. While his film appearances became less frequent, he worked steadily in theater (with the Royal Shakespeare Company, primarily) and in television, notably as the unperturbable butler in "Two's Company" (1975) and as a miserable in-law in "Never the Twain" (1981).