The 38-year-old, who plays Queen Vic landlord Mick Carter, opened up about the incident at the famous Pinewood Studios.
“We went to Pinewood and we did it properly and I’ve got to say some of that stuff under the water, I was actually fighting for my life in real life.
“I couldn’t quite find the surface,” he said.
The underwater stunt features in a 30-minute special due to be broadcast on New Year’s Day.
Danny Dyer and Matt Di Angelo (Jack Barnes/BBC)
The episode is focused around the wedding day of Mick and Linda (Kellie Bright).
It will see Mick’s rapist brother Dean (Matt Di Angelo) make an unwelcome appearance.
The two siblings will end up in the water after a dramatic turn of events prompted by an increasingly unhinged Dean.
Danny Dyer in EastEnders (Jack Barnes/BBC)
“We did this big epic battle, me and Dean, it’s a sad, sad, story. The idea that he is me brother, it could’ve been so different. It tailed off into this madness,” Danny stated.
“I had to have me ear-hole syringed – a lot of lake in my ear-hole. It’s a strange feeling, but we’re committed to it. You’ve got to commit,” he continued.
“We’re all committed as actors, producers, writers, directors – we love the show. We’re obsessed with it.”
Danny Dyer and Kellie Bright (Keiron McCarron/BBC)
Danny was speaking at a press event showcasing festive storylines for the BBC soap. EastEnders producer Dominic Treadwell-Collins and actors Laurie Brett (Jane Beale) and Richard Blackwood (Vincent Hubbard) alos attended.
Danny explained how he came to be involved in his character’s ‘naughty’ stag do at the Queen Vic.
“Dom came to me and he said, ‘Look, I want a Danny Dyer stag night.’ I said, ‘You f*****g sure, mate?’”
He revealed the celebration will include an Oasis tribute band called Noasis.
“They gave me a bit of input into it. I thought, well, I’m running the most famous pub in the world so we’re going to have it there, obviously.”
“I love Oasis… that was Oasis in that [clip], by the way. We got them all together,” he joked before admitting it was Noasis.
Danny described being a member of the EastEnders cast as ‘rewarding’.
“You never get used to being in this sort of show. It is very, very hard work. It is so rewarding,” he stated.
“You come home drained, but you actually go, ‘It’s worth it’. You sit down and you watch it and you go, ‘Wow, I’m part of that’.
“That’s a beautiful thing. So to have a stag where I had an input, a bit of a say in it, I’m really proud of that. It’s a naughty stag, I tell ya!” he cried.
EastEnders’ two specials will be broadcast on New Year’s Day at 6.30pm and 8pm.