Andrew Lincoln thought he'd stumbled across an "accident" when he shot his first ever scenes for 'The Walking Dead'.

Andrew Lincoln

Andrew Lincoln

The 43-year-old actor only truly got an idea of the scale of the show when he arrived for filming his first scenes as Rick Grimes, in a sequence where his alter ego shot a zombie girl in the head.

He recalled: "I remember coming up and seeing this turned over Mack truck and thinking, 'Holy s**t, there's been a f***ing accident!'

"And then someone was like, 'No, you're in the right place. This is your set.'

"That was the beginning of realising the scale of the show, so walking through that gas station set-up was just thrilling."

And the British star admits it was a "terrifying" experience when he first started shooting the show.

He told Entertainment Weekly magazine: "It was the most incredibly immersive experience -- and terrifying. And that set the tone and the bar for what that first season was all about. It was extraordinary.

"It was lots of big expansive setting up of that world, and that's what I've always seen that first season as being -- a man wakes up into a new world. So there was a great ambition in set design and scale that I don't think we've really backed away from much."

Andrew recalls feeling "distressed" by the scene and spent a lot of time apologising to Addy Miller, who played the zombie - and was amazed by the youngster's calm attitude.

He said: "Addy was amazing and the make-up was phenomenal.

"I had not met her without all of that, so I was just greeted with this terrifying apparition. I had been quite solitary. I really hadn't spoken to anybody, just because the nature of the story.

"So I just thought, well, this a pretty awkward moment because I'm going to have to get a 357 magnum and shoot this girl in about 30 minutes so I better introduce myself. And I said, 'Look, I'm really sorry about all of this and I hope you don't mind that I'm going to have to shoot you.' And I was really upset by this because it was the nature of the scene and I was kind of distressed anyway by the whole world.

"And she was like, 'I'm fine, just get on with it.' And she was eight or nine years old at this point and telling me, 'C'mon man, get to work. We're professionals here.'

"So she was completely comfortable with the entire idea. And I was groveling around, trying to apologise for the next hour, and she was magnificent.