A Reddit user correctly predicted the biggest and most shocking twist in Harry Potter and the Cursed Child way back in September, when the plot of the play was still top secret.

Major spoiler warning. Do not read on unless you want to know (or already know) The Cursed Child’s biggest surprise.

The official eighth story introduces one hell of a development which’ll have fans talking for years: Voldemort and Bellatrix Lestrange had a child, and her name is Delphi. Initially introduced in the play as the niece of Amos Diggory, we later learn that Delphi is actually the daughter of Voldemort, and wants to go back in time to meet her father. By the end of the play Harry tells her that she must deal with being an orphan — just as he has.

After seeing both parts of the play last week, Hypable’s writers privately debated who the “Cursed Child” is. We all had different answers, and we will discuss this at greater length here on the site once the script book is out, but one of our theories was that the Cursed Child is Delphi.

Funnily enough, Reddit user sappy6977 had the same guess last year before we knew anything about the play, and went so far as to come up with a solid theory about how Bellatrix giving birth to a child fit into the Harry Potter books:

You ever notice how Bellatrix Lestrange is not there when Snape kills Dumbledore on the tower (in the book, anyways)? Why wouldn’t Voldemort’s most dangerous lieutenant, and Draco’s aunt be there? At the beginning of HBP, Bellatrix says something strange… “If I had sons, I would be glad to give them up to the service of the Dark Lord!” Notice how she said sons, not a son.

In DH, it says 3 times that Bellatrix talked to Voldemort as a lover and her death is the only time Voldemort is upset at someone’s death.

My theory is Bellatrix was pregnant at the beginning of HBP when they saw Snape with Voldermort’s child. She is thinking of the future and says sons instead of son because she already has one on the way. She is missing from the battle because she is off giving birth to Voldemort’s child. She changes how she speaks to him after OOTP and Rowling even tells us how. And it’s why Voldemort insists on Bellatrix getting rid of Nymphadora and keeping her family tree pruned. Therefore, I think the cursed child is Bellatrix’s child with Voldemort. And that the plot will be if a child is born bad because of their parents or if the child has a chance to be good despite.

We all know that J.K. Rowling is very capable of excellent foreshadowing, so maybe this theory is correct, and the Harry Potter author had it planned this way all along. On the other hand, Rowling was very clear at the end of writing the Harry Potter series that she was done with the story for the foreseeable future. So would she really have let such a big twist like this lie in hiding for nearly nine years? Remember, this play only came out because someone brought the idea to her — the story wasn’t initially her idea.

We hope Rowling one day addresses this theory, as it seems to fit pretty well.