It was reported last month that Albert Square's B&B will go up in flames, with the soap's team building a replica set at Elstree Studios to film the shock blaze scenes.
The fire is started deliberately and causes a massive explosion, leading to the climax of the Masood and Yusef Khan (Ace Bhatti) storyline, according to the Daily Star Sunday.
Zainab (Nina Wadia) is under the complete control of Yusef, who is attempting to make her return to Pakistan with him. When the fire breaks out, Masood (Nitin Ganatra) is living in the B&B and Zainab desperately tries to reach him, much to Yusef's dismay.
The cast recently filmed the episodes, due to be aired at Christmas, and Preeya Kalidas (Amira) tweeted that the explosion on the special Elstree set felt like an "earthquake".
An EastEnders spokesman told the paper: "We do not comment on storylines as we don't want to spoil it for our viewers."
Speaking of her character's Christmas storyline, Wadia recently told Digital Spy that the scripts "shocked the life out of me".
"I'm literally thinking, 'Oh my God, oh my God, what's going to happen next?'" she said.
> EastEnders Nina Wadia on new film, Zainab shocks and more: Interview