EastEnders viewers were left stunned this week, as Monday's episode confirmed another member of the Knight family.
George Knight has a secret son, while this was kept back from spoilers and the son's identity has not been revealed.
The character hasn't even been mentioned, but viewers are convinced we could meet him soon.
While one fan joked it could be a familiar face, others were sure the mystery son was going to be linked to the big Christmas Day episode later this year.
Fans know that a male character, yet to be revealed, is being killed off at Christmas, with six female suspects in the frame for the crime - all of which was teased in a flashforward clip.
Amid speculation George will be killed, the revelation about his secret child has led to a new theory given the crime happens at George's pub.
In a chat with Phil Mitchell on Monday, George confirmed he had a son who "goes off the rails", adding: "I don't see much of him - his choice, not mine."
The conversation ended there before any more details about the son or who he was, or why he and his father are estranged.
With the sisters not yet mentioning their brother, it's not known if they are in contact or if the son vanished around the time that George's wife apparently walked out on them all.
Taking to Twitter, fans were convinced that the secret son of George had something to do with the looming Christmas twist, and might even be the character who dies.
One fan tweeted: "Missed the bit where George mentioned he has a son when talking with phil. Could he possibly have something to do with the six? Will he get introduced?"
A second viewer said: "I am guessing this could all tie in with Cindy's return #TheSix," as a third added: "George Knights son ends up dead on the floor at Christmas."
As speculation over his identity grew, one fan commented: "Would love it if George Knights son turned out to be Fatboy…"
It comes after viewers believed they knew the identity of George's ex-wife, who has not been introduced on the BBC soap.
With EastEnders teasing the family or George have "a dark past", viewers believe George's missing wife could be a familiar face.
Viewers know that his ex hasn't been a part of their lives for some time and her whereabouts are a mystery, while it's claimed that she walked out on the family when the girls were younger.
There's been speculation that returning character Cindy Beale could be the mystery wife of George, and mother to his daughters.
Fans say a number of clues teased a possible link between the former Walford villain and the new family, while it's yet to be confirmed who their mother is and where she went.
Taking to Twitter, one fan said: "So what are we all thinking? Cindy beale could possibly be gina and anna’s mother? The (what i assume was) anna’s jewellery box and anna saying walford already felt like home….."
Others recalled that Cindy had a sister called Gina on the BBC soap, as one pointed out the possible jewellery box link.
Another viewer said: "That scene with Anna & Gina talking about their mum and the jewellery box definitely meant something."
A third fan commented: "George's partner Elaine tells her daughter, Linda Carter that the mother of his girls walked out on them 9 years earlier and 'never looked back.' Now, what else of note happened back in 2014? Cindy's eldest daughter, Lucy Beale was killed in a shocking 'whodunnit' storyline."
Another fan wrote: "Definitely not a coincidence that Anna and Gina had scenes with Bobby and Kathy tonight!"
EastEnders airs Mondays to Thursdays at 7:30pm on BBC One and BBC iPlayer.
