The actress's troubled alter ego Zainab Masood reaches breaking point this week, finally telling her family how she vengefully sent her abusive husband Yusef Khan back into the burning B&B at Christmas.
Speaking on Lorraine this morning (March 6), Wadia confessed that she was surprised by how much the scenes affected her on set.
"We were filming mid-January, and I suddenly had a massive breakdown in front of everyone! It was really embarrassing," she explained. "I just cried in the middle of a scene, I just absolutely burst into tears.
"It was Zainab talking about what had happened, and then I just uncontrollably couldn't stop and it was horrible. Luckily Nitin [Ganatra] and Marc [Elliott], who play Masood and Syed, were there. They literally just took me aside, sat with me and calmed me down. I apologised to the director, because I physically couldn't stop crying."
Wadia said that she hopes a happy ending is on the horizon for Zainab and Masood, despite the turmoil ahead for the family following her character's confession.
"Zainab's been living with this for a few months now and she finally can't take it anymore," she commented. "So it all comes out, and it comes out in the worst way possible, in front of everyone. I think she probably would have liked to confess to Masood privately first, but she didn't get a chance.
"It all has gone very wrong for her since Christmas. But I'm hoping, I'm really hoping, at some point they get her and Masood back together."
EastEnders continues tonight (March 6) at 7.30pm on BBC One.
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Watch Zainab's EastEnders character trail in the video below: