Warning: This article contains spoilers - do not continue reading if you do not want to know how Curtain: Poirot's Last Case ends
The final curtain has fallen on Poirot's last case, and fans of the long-running drama will now have to mourn for their favourite Belgian detective.
Tonight, David Suchet made his final appearance as Poirot after 25 years in the ITV series, shocking viewers as he turned murderer, taking the life of a psychopath in order to protect others, before killing himself.
Suchet has now performed every one of the stories Agatha Christie wrote about the quirky supersleuth.
But it was a very different Hercule Poirot that viewers bid adieu to tonight - old and ill, he was not the dapper and confident fellow who struts about with his cane.
Suchet recently revealed he achieved Poirot's distinct walk by clenching a penny between his buttocks.
But his swansong saw him hunched in a wheelchair, having to be carried up and downstairs.
And the actor, who usually has to be padded out to play the gourmand with a weakness for chocolate, had to lose two stone to achieve his thin and frail appearance in Curtain.
Set during the Second World War, the story had a very different mood and appearance to the glamorous art deco extravagance of classics such as Death on the Nile and Murder on the Orient Express.
Christie wrote the story during the war, at a time of uncertainty that is heavily reflected in the story.
Poirot resides in a remote and gloomy country house, appearing paranoid and melancholy as he rants his certainty about a murder that had yet to take place.
But the detective's "little grey cells" were as sharp as ever and there was still humour to be found in the episode.
There were plenty of the usual extravagant, eccentric characters in the form of the other guests.
Reunited with old friend Hastings - played by Hugh Fraser - the pair bickered like a married couple as Poirot proved as demanding as ever.
When Christie wrote the last Poirot novel telling of the character's death in 1975, the New York Times published a front-page obituary with the words, "Hercule Poirot, a Belgian detective who became internationally famous, has died in England. His age was unknown".