Speaking about the moment, the comic told What's on TV: "I said to the director, 'Should I tell the actor that I don't fancy him?' And she was like, 'No that's rude, don't say that!'
"But the actor was really cool about it and we called each other dude quite a lot. But he was a lovely kisser. I just kissed him how I'd normally kiss someone.
"Simon sort of gets kissed as opposed to instigating it, so I could appear a bit tense and anxious about it so that was alright. But watching it back I was like, 'Oh my God!' That's a strange thing to see'."
Amstell further explained: "I was very tense and I think we filmed that scene at about 8am. It was also something that hadn't appeared in the script when the actor auditioned.
"The bathroom scene where it takes place did not exist in the original script. So we improvised some fabulously awkward stuff handing over this towel in the bathroom."