Damien Molony and Michelle Keegan had "a good laugh" shooting their "Brassic" portable toilet sex scene.
The Irish actor and "Our Girl" star appear as couple Dylan and Erin, and he revealed their characters shared a steamy moment during a "bizarre" first day on set.
He told the Irish Independent newspaper: "There's nothing sexy about a "Brassic" sex scene.
"They're always such bizarre things anyway, but it was definitely odd having sex in a portable loo on your first day of a new job, definitely a tight fit.
"It's just a good laugh because you both understand the complete ridiculousness of the situation."
The show follows a group of working class friends looking to survive in suburban Lancashire through scamming, conning and bribing.
Leading man Joe Gilgun's character Vinnie had a troubled childhood - his mum left and he was raised by his alcohol dad - and faces a constant battle with bipolar disorder.
He previously heaped praise on the quality and work ethic of the group of performers gathered together for the new show.
Joe said: "We're incredibly lucky to have the cast we've got. Honestly, they're flawless... I keep using this bloody analogy; some actors you can let them off the lead and they'll wonder about and have a s**t and a p**s, they mix well with other dogs, you don't have to worry about them bolting off if they see a cat, these are them.
"There are other actors, you let them off the lead and they just f**k off. My lot are mint. We really have picked a f***ing great group here. We do get on, we all really get on."