BILLY Mitchell is left stunned after he discovers a shocking family secret in EastEnders.

The character – played by Perry Fenwick – has had a number of surprises in recent months, with partner

Honey proposing after the London Marathon, before estranged dad Stevie Mitchell showed up.

While Billy wanted nothing to do with his dad after the way he had treated him when he was growing up, Stevie (Alan Ford) decided to stick around in Walford anyway.

Stevie has slowly been building bridges with the Mitchells, but in tonight’s episode, he is accused of stealing the money raised at a talent show in honour of Lola Pearce, who died last year.

In upcoming EastEnders episodes, Billy and the rest of the Mitchells point the finger of suspicion at him, leaving Stevie on a mission to track down the real thief.

At the café, Stevie tries to probe Billy’s son Will about his involvement – knowing he is being blackmailed – but in a desperate attempt to throw Stevie off the scent, he points the finger elsewhere.

Later in the pub, Will fiercely defends Stevie to Phil and storms off when Phil won’t entertain Stevie’s innocence.

Seeing his grandson heading home, Stevie follows Will and gets him to admit what he did.

Stevie counsels Will to confess and loses his temper when Will refuses.

In a moment of madness, Will knocks Stevie over and rushes off, leaving his grandad motionless on the floor.

Thankfully, Phil sees Will bolting out of the flat and goes in to find unconscious Stevie and calls the ambulance.

The Mitchells all rush to the hospital and Phil confronts Will about what happened.

The teen confesses everything leaving Phil to go and find Kyle, the boy blackmailing Will.

Back at the hospital, doctors tell the relieved Mitchells that Stevie has a concussion but will be OK.

But they receive a shock when back on the Square, three new faces arrive looking for Stevie – Teddy, Harry and Barney Mitchell.

Billy tells Stevie that he’s glad he’ll be OK, but they are finished as family.

Will lags behind and apologises to Stevie, who is quick to console him, but he’s soon shocked to see Teddy, his son.

Sending Will off, Stevie lies to Teddy about where he’s been and doesn’t tell him who Will is, but curious Teddy makes it his mission to find out the truth…

Teddy sees Will with Billy and follows them back to Albert Square.

Later, Billy gets a text from Elaine to say Will is in the bar with a man she doesn’t recognise.

Everyone rushes to The Vic, where it looks like a fight is about to kick off until Stevie reveals that Teddy is Billy’s brother…

Billy is reeling at Stevie’s revelation, but Teddy demands to know who put his dad in hospital.

Tempers flare as accusations fly, and Stevie has a lot of explaining to do about the secret family he’s just introduced.

Overwhelmed, Billy rushes off as Stevie follows, leaving Teddy and Phil to cross swords.

EastEnders airs on BBC One – but also BBC Two depending on Euros coverage – and is available on BBC iPlayer.