Vera Duckworth is to be killed off in a tear-jerking Coronation Street storyline to be screened early next year, ITV has announced.
Her departure will be filmed in secret and viewers will not know how she dies until they watch her final episode.
Liz Dawn, 68, who has played Vera for more than three decades, is leaving the soap due to ill-health.
A lifelong smoker, the actress was diagnosed with lung disease emphysema five years ago.
Dawn revealed the disease had taken such a toll that she was barely able to walk across the set and nearly collapsed while at Buckingham Palace to collect her MBE in 2000.
The decision to kill off the character was taken after long consultation between producer Steve Frost, executive producer Kieran Roberts and the actress herself.
They all felt it was better to have a dramatic finale rather than compromise the characters of Vera and her husband Jack by having Dawn come back for occasional guest appearances in the future.
"It is going to be very emotional filming Vera's death scenes but I do think it is the right decision for the character," Dawn said.
"Steve Frost and Kieran Roberts were very respectful about how I would feel about Vera dying and we talked about it at length before we made the final decision.
"I have had 33 marvellous years in Coronation Street and will miss everyone very much," she said.
The soap's producers are so keen to keep Vera's cause of death under wraps that three alternative endings have been written.
Letters have also been sent to newspapers and magazines asking them not to leak any details of what happens to the character.
Producer Steve Frost said: "After discussions with Liz Dawn we have settled on a heart-breaking exit story which will see Vera leave Coronation Street in 2008.
"Liz's contribution to Coronation Street has been quite remarkable.
"She has played Vera, one of the most loved characters on British television, for 33 years and she will be missed enormously, by everyone who works with her on the show and by millions and millions of viewers," he said.