Eagle-eyed EastEnders fans spotted a major blunder on the BBC soap this week, during a frantic scene.
Chelsea Fox desperately called for the emergency services after finding her husband Gray Atkins laying in a pool of blood.
He'd been attacked by Kheerat Panesar after a deadly showdown, as Gray had tried to attack him first.
Kheerat was in shock and delayed calling for an ambulance, as Chelsea burst into the room and found Gray lifeless on the ground.
As she realised help had not been called for, she decided to call for an ambulance and told them what had happened.
Viewers were furious as she also told them that Kheerat was the attacker, and was still at the premises, forcing him to do a runner and flee Walford.
But some eagle-eyed viewers spotted something about the scene that left them amused, as a frantic Chelsea made a big mistake.
As she dialled the number on her phone and explained what had happened, viewers quickly realised she had her phone upside down.
While it seemed to be the right way around at one point, moments later it was visibly upside down with the camera shown on the bottom and not the top.
The charger slot was also no longer visibly, and when she pulled the phone away from her face it was still visibly upside down.
Viewers were quick to spot the moment, with many taking to Twitter to see if anyone else had noticed.
One viewer said: "Did anyone else notice when chelsea rang for an ambulance for Gray her phone was upside down."
Another tweeted: "@bbceastenders… can you explain why I’m watching an error that should have been picked up by your editing team? Look at the phone!!"
A third added: "Not Chelsea making a call with the phone upside down & then it’s the right way round..." as another tweeted: "Not Chelsea phoning an ambulance with her phone upside down."
EastEnders airs Mondays and Fridays at 8pm, and Tuesdays and Thursdays at 7:30pm on BBC One.