Remembered for his title role in the 1980s and 1990s Granada Television adaptations of the Sherlock Holmes stories, Brett is also known for his portrayal of Freddy Eynsford-Hill in the 1964 film version of the musical My Fair Lady.
During his early years, he suffered from both dyslexia and a speech impediment known as rhotacism. He later overcame these difficulties; graduated from London's Central School of Speech and Drama; and went on to perform in several professional stage productions.
While he was playing the title role in a 1959 production of Shakespeare's Hamlet, Brett was deeply affected by the sudden death of his mother in an automobile accident.
Born Peter Jeremy William Huggins, he grew up in Berkswell, England. After his marriage to actress
He shared the screen with Audrey Hepburn in both My Fair Lady and the 1956 film version of War and Peace.