Taking to social media, one viewer wrote: "I wonder if as Phil enters into a mental health facility he will find Shirley is also there?
EastEnders viewers have been following along anxiously as Phil Mitchell's psychosis storyline took a dramatic turn last week, with a trip back in time that resulted in an apparent attempted suicide, and are now predicting a major character will return.
In recent weeks, fans of the BBC One soap have seen Steve McFadden 's character Phil struggle with his mental health.
But this was all in Phil's head, with Nigel waking him up as Phil appeared to be confused.
Viewers of the soap will remember Phil and Shirley's tumultuous relationship, which ended when she discovered his son Ben murdered her best friend Heather.
