This is a character McCarthy has been living with for some 15 years, having created her as part of her stand-up improv routine when she was with The Groundlings. "For me, my favourite character that I created was always Michelle Darnell," McCarthy says. "I loved her so much that I couldn't let her go, and I would randomly bring her up in conversation and talk about her over the years. She's a tricky one, though, because she is so dynamic, so forceful and so confident. Yet Michelle is someone who makes you wonder what lies beneath it all when she says, 'I don't need anyone - other than myself.' In the weirdest way, no matter how extreme she was, she always kind of made sense to me."

McCarthy asked many big names to appear in the film including Kathy Bates
McCarthy asked many big names to appear in the film including Kathy Bates

Working with her husband, director Ben Falcone, McCarthy was determined not to make a movie that felt like a sketch comedy stretched to feature length. "It's not that Michelle changed very much," she says, "but we figured out how to change or expand her world. We wanted to take this character who had enjoyed everything she ever wanted, but was kind of a terrible human being, then take all of the good stuff away from her and see what she does about it. That's a wonderful journey, I think."

She also decided to insert a fight scene that is sure to get everyone talking, as Michelle brawls with her former assistant Claire, played by Kristen Bell. "Ah, yes, the whole bra-la-la-palooza fight scene," McCarthy laughs. "When we wrote it, we were like, 'Will Kristen want to go that far?' Then she was, 'Oh, let's really get into it.' So we both got a little feisty and we just really went for it. At one point, I was laughing so hard because I suddenly became aware that we were actually doing all of this crazy stuff on camera. I'm quite sure I've never seen an epic boob fight in a movie before. I didn't want it to be some slap and tickle thing; I wanted a mauling, like Leo and the bear in The Revenant!"

Watch the trailer for The Boss: