Liar's unpredictable finale will surprise viewers with its revelations.
Airing Monday nights at 9PM, Liar has been pulling in millions of viewers for ITV.
The six-part thriller tells the story of a night that changes the lives of Laura Nielson (Joanne Froggatt) and Andrew Earlham (Ioan Gruffudd) forever.
Ahead of the final episode this evening, actress Shelley Conn - who plays DI Vanessa Harmon - has been teasing what's still to come.
"It's a controversial subject and I think the way it was set up, a who's lying [situation], it could have gone either way," she told ITV's Lorraine this week.
Shelley added: "Once there was the revelation and we found out who was lying and who was telling the truth, you thought, 'Oh where's this gonna go?', and I think that's the genius of the writing of Jack and Harry Williams.
"It's so unpredictable. They can bring things out that you didn't... I don't think anyone expected what happened to me to happen. As the show goes on, and it's the final episode next week, there are more revelations and you will be surprised."
Co-star Joanne Froggatt previously suggested that the series finale would not be "too open-ended."
"It's definitely a thriller that you can watch and get to the end and feel like you can pay back for your investment and time and emotion into this story," she told Entertainment Weekly. "It's not something that's too open-ended — it's a whole story, and a real roller coaster of a story."
That said, there have been rumours of a second series based on the events leading up to the first.
A source told The Sun newspaper: “Explaining the characters would appeal to fans who’ll be intrigued to see what underlying experiences sparked their actions.
“Bosses feel it would be the best direction to go in.”
Liar concludes tonight at 9PM on ITV.