Fans watched on as Bernadette (played by Clair Norris) kept tight-lipped about who was the father of her unborn child, much to mum Karen's (Lorraine Stanley) dismay.
Urging Keanu (Danny Walters) to investigate further, her step-son was keen not to leave Bernadette to her own devices, but as he entered her bedroom to talk to her, things became more and more unsettling.
After checking that abortion was not an option, Keanu assured Bernadette that he would financially support her, so long as neither of them shared their secret with their mum.
Keanu was revealed as potentially the father of Bernadette's baby
Is Bernadette hiding the real identity of her father's baby?
Although the words weren't said exactly, fans quickly jumped to conclusions, assuming that there was a "disgusting" incestuous relationship on the Square.
One viewer posted on Twitter: "Oh dear so the brother is the father #EastEnders."
Another added: "Ew I f***ing knew it was her brother!!! Rotten #EastEnders."
Viewers were outraged by the reveal
A third agreed, saying: "I b****y knew she was preggo by her brother! How incredible uncomfortable it's becoming. First stalky Steven and Abi, now this #EastEnders."
A fourth tweeted: "Did #EastEnders really just go there with that story line….. #Yuck."
Is Keanu really the father, or does he just know who it is and wants to offer his help innocently to his step-sister?