Roger Ebert, 67, America's first film critic to win a Pulitzer, in 1975 and a household name in US since launching his TV show, At the Movies, in 1982, had to give up live broadcasting in 2006 when he lost his voice after operations for thyroid cancer.

For the last troublesome four years, Ebert communicated through hand-written notes, simple sign language and with the aid of a basic voice synthesizer, but now he will appear on the screen for the first time since the surgery, on The Oprah Winfrey Show, using his own voice.

Ebert contacted a Scottish company, CereProc, based at University of Edinburgh which produces customized voice synthesizers that translate text to speech and deliver it in the voice of its author.

They painstakingly reconstructed his voice, piecing together snippets of recordings of archive of his TV tapes, DVD commentaries and radio shows to produce new words and sentences. He is pleased with the results and is keen to demonstrate it in public.

Matthew Aylett, the Chief Technical Officer of CereProc, said, "We're giving Roger Ebert actually the same voice he had before the surgery. When he uses it, people who listened to his commentaries in the past as a broadcaster will recognize his voice".