Millions of soap fans tuned in to watch EastEnders' first live episode and find out who killed Archie Mitchell.
Stacey Branning confessed to the murder in the closing minutes of the show, revealing what's been one of the best-kept TV secrets of recent years.
Ten possible endings had been rehearsed and even Lacey Turner, who plays Stacey, didn't know she was the killer until 30 minutes before the show began.
The BBC said 16.6 million people had watched the 25th anniversary episode.
Stacey and Bradley had been about to run away from Albert Square
The live show, which went smoothly apart from a couple of fluffed lines, also included the death of a main character.
Stacey's new husband Bradley, who's played by Charlie Clements, fell to his death off a building in Albert Square, prompting Stacey's shock confession.