The Undoing's second episode dropped on Sky on Monday, and it's fair to say that viewers are already seriously invested in the murder mystery thriller.
READ: The Undoing: Who killed Elena in the thriller starring Nicole Kidman, Hugh Grant?
The series, which follows Hugh Grant and Nicole Kidman as married couple Jonathan and Grace who find themselves at the centre of a murder investigation when a young mum from their son's school, Elena, is found dead. Warning, spoilers ahead for episode two!
WATCH: The Undoing is THE show everyone is talking about right now
In the second episode, it is revealed that Jonathan was having an affair with Elena, whose son was one of his patients. He then lost his job as a result of the relationship and disappeared shortly after she was found dead.
However, he appears in the final moments of the episode, having remained hidden at his family's beach house, and swears to Grace that he had nothing to do with Elena's murder. So who did?
Elena is murdered in episode one - but who did it?
Viewers have been quick to share their theories on who really murdered Grace, with one tweeting: "At this point everyone is a suspect. I mean the killer could be me for all I know." Another added: "Blonde haired friend is super weird."
MORE: Nicole Kidman's daughters have roles in The Undoing - details
MORE: Nicole Kidman rocks shorter shaggy hairstyle - and looks incredible
READ: ALL you need to know about The Undoing - from famous cast to the killer
A third person wrote: "Grace’s dad (Donald Sutherland) I figured he knew what was going on & wanted to clean up his son-in-law's mess. Just a theory."
Was Grace herself involved?
Another fan believed it was either, Jonathan or Grace, explaining: "1) Grace found out about the affair & killed Elena out of jealous revenge or 2) Jonathan saw Elena getting close to his wife & encroaching on his family. Elena crossed too many lines. Killed her to keep her silence."
Other suggestions included the couple's teenage son or a character from Elena's past who we have yet to meet. We can't wait to actually find out!
Like this story? Sign up to our newsletter to get other stories like this delivered straight to your inbox.