McCallum realises her show - which includes bad-taste jokes and sexual references - is likely to be controversial.
But she believes Stand Up Girl addresses some important issues.
"I wanted to make sure this series wasn't a factual account of being a sex worker," she says. "I didn't want to have that kind of responsibility. I wanted to honour it as truthfully as possible, but also acknowledge the fact that I am not one and have never been one.
"I think it's important that we acknowledge these pockets of society that often get misrepresented."
The show is inspired by Lucy Roche, a stand-up comic and sex worker whom McCallum saw perform. The idea came when her set sparked "a really interesting discussion" among McCallum's friends after the show.
"As feminists, we were on board, but as people ... where do you stand? It was confronting, and weird, and when I found out she was a sex worker, I was surprised ... it came from that really."
McCallum says she wrote Stand Up Girl independently, but has Roche's blessing.
And she has big-name Kiwi talent backing her for the six-part series, including Game of Thrones star Joe Naufahu, The Expanse's Frankie Adams, and Westside's Antonia Prebble.
She also did thorough research, interviewing several sex workers about their experiences to help portray their profession "with integrity and respect".
But she admits she had to Google some of the terms Jan uses during her stand-up shows.
"I wanted something funny and I went down this hideous list of things ... there were a couple [that were unusable]."
Watch an interview with Joe Naufahu below:
As for the stand-up comedy, McCallum says she's unlikely to grace a stage at The Classic anytime soon, after struggling to get through Jan's sets for the show.
"It's terrifying. Even though I had the lines, I knew people had to laugh at me, and I knew it would be cut in a good way, I was like, 'This is horrible'."
