Evil Graham befriended Little Mo then attacked her (Picture: BBC)

An evil ghost from the past is set to return to Walford as EastEnders revisits a horrific attack on Little Mo Slater (Kacey Ainsworth), almost 18 years since it happened.

Freddie (Bobby Brazier) remains curious about his real father, having learnt that Billy Mitchell (Perry Fenwick) isn’t his biological dad.

Viewers know that Graham Foster befriended and gained the trust of Little Mo when she worked at the Queen Vic.

As he spent months propping up the bar, he invited himself in after hours, and when Little Mo tried to coax him out, frightened for her own safety, he raped her in a despicable act.

She would later give birth to Freddie, refusing to feel ashamed for keeping a child that should bear no blame for the actions of his father.

It was something which ultimately Billy couldn’t handle, and it led to Little Mo taking Freddie with her as she left for a new start.

Freddie has made himself at home with his extended family, showing off a cheeky personality, and building an endearing bromance with Bobby Beale (Clay Milner Russell).

But this spring, as previously confirmed by show producer Chris Clenshaw to Metro.co.uk, he will discover the truth about his father in emotional scenes, after an unlikely source reveals the name.

On returning to EastEnders, actor Alex McSweeney said: ‘I was grateful to be asked back to EastEnders to reprise the role of Graham Foster as I thought it was important for Freddie Slater to be given some answers about his dad.

‘It was great to be back in Elstree and I thoroughly enjoyed working with the talented Bobby Brazier on these scenes.’

Graham’s horrific attack left Little Mo traumatised (Picture: BBC)

Graham’s return comes almost 18 years after the original story (Picture: BBC)

Chris Clenshaw, Executive Producer, added: ‘It’s great to welcome Alex back to the role of Graham Foster for a short stint.

‘Although we haven’t seen Graham for almost two decades, his character has been heavily linked to the show in the past year with the reintroduction of his son Freddie Slater, played by Bobby Brazier.

‘We felt that it was important for Freddie to find out about the circumstances relating to his conception so he can understand and process the identity of his dad.’

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The episodes will air later this month, and Metro.co.uk understands that Little Mo will not be back at this time.

The soap is working with Rape Crisis on the execution of the storyline.

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A horrific blast from the past brings a nightmare to the Square.