Ever since Stacey Branning (Lacey Turner) shared a snog with best friend Shabnam (Rakhee Thakrar)’s husband, we knew there was going to be trouble.
And it seems as if it’s all set to come to a head this Christmas 2015, when EastEnder’s veteran Stacey gives birth to Kush (Davood Ghadami)’s secret baby.
As if that wasn’t dramatic enough, Stacey’s bundle of joy will arrive smack-bang in the middle of Albert Square’s nativity play - on Christmas Eve.
Well, a press release from the BBC about the forthcoming drama states: "As Stacey watches Lily perform in the Nativity Play, she suddenly goes into labour..."
Sneak-peek photos show Stacey sharing a tender embrace with boyfriend Martin Fowler (James Bye), who believes that he is the father of her child.
But there’s heartbreak on the horizon, as the baby’s real father, Kush, is also there to witness the birth.
And an increasingly-suspicious Shabnam, who tragically delivered her own stillborn son earlier this year, is at his side.
It seems as if Stacey’s big secret will be exposed before too long - and it marks the beginning of a traumatic 2016 for the much-loved character, who is set to be diagnosed with postpartum psychosis.
As EastEnders viewers are aware, Stacey Branning was diagnosed with bipolar disorder in 2009. Although postpartum psychosis can affect a woman without pre-existing mental health issues, it is more likely to affect a mother who has bipolar disorder.
Dominic Treadwell-Collins, the soap’s executive producer, said: “Stacey's mental health story will be one of our biggest storylines over Christmas and the beginning of 2016 as we explore Stacey's bipolar disorder and its effects on her and those closest to her.
Praising the talented actress who portray Stacey, he added: “Lacey is one of the most raw and intuitive actresses on television and it's exciting to watch her getting her teeth into a really intense storyline as Stacey battles against the world.
“With the truth about Stacey's baby's parentage bubbling underneath and the final reveal of the meaning of Stacey's key, this story is going to place Stacey right in the centre of a very big storm...”
This episode will air at 8.30pm on Christmas Eve on BBC One.