EastEnders’ Nicola Mitchell has made a surprise discovery about a secret betrayal, in the show’s latest episode.

This week, Barney overheard Sharon and Zack talking and found out that Sharon had cheated on Teddy by sleeping with Grant.

Barney confronted Zack about this, but he was suddenly rushed to hospital when his wound from the pub explosion started bleeding.

At the hospital, Zack got suspicious after asking the nurse about blood groups, and he asked Nicola if he was Barney’s real dad – considering they had a fling 16 years ago.

In today’s episode, Nicola confirmed that she has always known that Zack is Barney’s biological father. Teddy caught them talking and asked questions, but Nicola managed to hide the truth from him.

Zack struggled to come to terms with this bombshell and began drowning his sorrows at Harry’s Barn. Back at home, Tommy gave him pause for thought when he admitted that while Alfie isn’t his biological father, he still sees him as his dad.

Things got worse for Zack when Whitney cancelled his time with Dolly this weekend. Concerned Ruby went to check on him, and Zack confessed that he had discovered he has another child.

After the pair had an emotional chat, Zack tried to kiss Ruby but she pulled away, reminding him that Martin had only just died.

Meanwhile at the hospital, Teddy broke down in tears in front of Nicola, distraught that they could have lost Barney.

Zack went to see Barney but he was sleeping, and Zack didn’t feel able to tell him that he was his dad. However, he urged Nicola to tell him instead, saying that he needs to know the truth.

Barney later woke up and apologised to his mum, telling her that he had found out something to do with Zack and leaving her concerned.

But what Nicola didn’t expect him to say is that he heard Sharon and Zack talking about her betrayal with Grant.

What will Nicola decide to do with this shocking new information?