Coronation Street's live birthday treat

Actors are said to be excited about the live episode

ITV soap opera Coronation Street is to broadcast a live episode to mark its 40th birthday.

The drama marks its anniversary on 9 December and the episode will be broadcast in the run-up to the date.

The show's first episode, in 1960, was broadcast live, as were many other episodes.

The show's producer, Jane Macnaught, said: "It will mean a lot of hard work for the cast and production team involved, but I know it will be an enjoyable and exhilarating experience."

American TV producers have experimented with the format recently - a live episode of ER pulled in 42 million viewers, with George Clooney appearing in another live drama, Fail Safe.

The first episode of Coronation Street was live

The plot is a closely guarded secret, but the show's spokeswoman revealed that one character will have a critical health condition, while a couple will face a personal dilemma, as cracks appear in their relationship.

Macnaught broke the news to the cast on Friday and said they were delighted with the idea.

Other events to mark the anniversary include a documentary about the life of actor Bill Roache, the soap's longest-serving star, who has played Ken Barlow since it began.

There will also be a tribute programme called Forty Years of Coronation Street.

Granada TV's director of programmes, Grant Mansfield, said: "Coronation Street's 40th anniversary is a major landmark in television history.

"The live episode is a fitting and evocative way to mark and celebrate one of the world's most enduring and popular programmes."