It is reported that Happy Valley executives have kept the BBC set busy over the course of the new season, filming five different endings to prevent the finale from being leaked.
Over six million are expected to tune in for next Sunday's huge BBC1 finale - as the West Yorkshire-based crime drama continues to grow in popularity.
Eager and excited fans have been left in the balance to see if Catherine Cawood (Sarah Lancashire) and her nemesis Tommy Lee Royce (James Norton) resolve their chase.
Read more: Happy Valley fans have theory for why Poppy never takes off her coat
The Mirror reports that as the drama ramps up, bosses are said to have been so concerned about the ending to series three leaking that they've taken drastic action to keep it hush-hush. Writer Sally Wainwright reportedly had to get busy, penning several alternative outcomes to prevent fans from working things out.
A show insider teased that the last ever episode will be 'epic'. But if you think you've worked out what's going to happen, then you probably haven't!
"The scripts were seen by those who needed to see them but even they haven't given away how things will come to an end because the scenes were filmed in different ways," the source told Mail Online.
"From the beginning of the planning of series three, Sally and her team wanted to end the show in a sensational way and give viewers an ending they won't forget - she also didn't want any spoilers to ruin things. It is going to be epic, and all the more so because nobody knows the ending. It has been really cleverly done to keep fans guessing right up until the very end."
Happy Valley's creator spoke before the launch of the third series and revealed the dark origin behind the show's title. Sally explained: "I always work closely with police advisors, who are old police officers who have worked in the area, and one of them told me that is what they call the Valley because of issues with drugs.
"For me, it reflected the show. It’s dark, but it has also got a lot of humour in it. I think less so in season one, more so in season two. We want to continue that in the new season. It’s still very much about the dark side of life, but it’s also about how within that people always find ways of being funny and warm and human."
But make the most of it while you can, because next weekend will be the last ever episode and bosses have explained why.
According to the Radio Times, Executive producer Will Johnston confirmed: “It definitely isn’t coming back – and again this is [from] Sally and Sarah who completely and rightly feel that you can have too much of a good thing.
“The two vital things are that Rhys [Connah, playing Ryan Cawood] is now at an age to make his own decisions about his life and the relationships in it, and [Lancashire’s character] Catherine’s on the brink of retirement, and those felt like such juicy things to explore."
The penultimate episode of Happy Valley returns on BBC1 at 9pm tonight before the season finale lands next Sunday
- Happy Valley fans spot massive clue that Catherine Cawood will die in BBC drama
- Happy Valley's Tommy Lee Royce sets up Catherine 'showdown' as fans raise death concerns
- Helen George in Call The Midwife 'separation' plot as actress makes career move
- Strictly's Kai Widdrington starts tour rehearsals after replacing co-star in partner 'twist'
- Strictly's Helen Skelton starts tour rehearsals as Gorka Marquez absence upsets fans