The following article contains spoilers from an episode of EastEnders that hasn’t aired on BBC Two yet, but is available to view on BBC iPlayer.

Billy Mitchell (Perry Fenwick) has discovered another major family secret in EastEnders.

Recently in the BBC One soap, Billy was introduced to three new members of the Mitchell clan after Stevie (Alan Ford) confirmed he started a family again after his mum left.

While Billy has warmed to the idea of getting to know his brother Teddy (Roland Manookian) and his sons Harry (Elijah Holloway) and Barney (Lewis Bridgeman), Phil (Steve McFadden) has been reluctant to sit down and learn more about them.

This is largely down to the fact Phil convinced himself Stevie was hiding something else from Billy, other than the new Mitchells.

In Monday’s (July 8) episode of the BBC One soap, it was Stevie’s birthday.

As Billy set about organising a party in the pub, he also spent time reminding people it’s his mum’s birthday today as well.

Elsewhere, Phil was at home speaking to the always iconic Ritchie. He instructed her to do some digging into Stevie’s background, certain his suspicions about him were correct.

Back in the pub, as Billy’s speech got underway, he mentioned his dad and his mum again, under the impression she was ‘out there’ living her life.

Just as the father and son hugged, Phil arrived and confirmed he had made a discovery about Stevie after all.

At Billy’s, as Teddy listened in on the conversation, Phil pushed Stevie to reveal the truth.

Stevie told Billy to open the card he had bought from the Minute Mart that morning. It was addressed tIt was then confirmed Stevie had known all along about the location of Val, because she died shortly after leaving the family when Billy was nine years old.

And to make matters even worse, Stevie then told Billy his mum’s death was his fault.

As if dealing with the arrival of Teddy, Barney and Harry wasn’t enough, how will Billy cope with this revelation?

And how did his mother really die?