The actress, whose character Mercedes McQueen is preparing to marry Riley Costello (Rob Norbury) in next week's special episodes, said that she and her co-stars managed to have a "laugh" while making the sinister, black-themed wedding clip.
Metcalfe told Heat magazine: "To be honest it was a long day for us. I'm used to doing 12 or 13 hour days on set, but this took 15 hours. It was one, big, heavy day. But we got so much out of it and it got us out of the office, so to speak - so it was all fun!
"I think everyone got in to the theme and feel of it. There were some right funny hairdos and stuff going on too, and people behaving really out of character. Outside of acting we all had a right laugh about it all, but at the time we all managed to hold it together and be totally serious."
Metcalfe admitted that the girl you see walking down the aisle at the end of the trailer was a stand-in rather than her, as she had to go home after 14 hours of shooting for "insurance purposes".
She said that the black paint that the make-up artists put in her eyes to make her cry a black tear "killed", adding: "It hurt. I have such sensitive eyes. I had my eyelashes dyed at the weekend, and even that was like the world was ending! You should have seen me. I'm just soft!"
Metcalfe also revealed that Mercedes has a "big" and "dark" storyline coming up after the wedding, saying: "[It's] something that's never been explored before with my character. It's been intense and hard work but I've loved every minute of it - I love seeing what my character's going to get up to."
Hollyoaks' wedding week begins on Monday, October 17 at 6.30pm on Channel 4.
> 'Hollyoaks' wedding: More pictures from Mercedes and Riley's big day
> 'Hollyoaks' teases Mercedes, Riley wedding blackmail - video
Watch the Hollyoaks wedding trailer below: