As The Boss opens, motivational-speaking, investment-guru Michelle Darnell (McCarthy) takes to the stage to much hooting and hollering. She raps for the benefit of her snake-oil customers: an army of dancers and pyrotechnics ensures that she nails it.

Indeed, our brash titular heroine seems to do little else but nailing or owning things, until, that is, her former lover and corporate rival Renault (Peter Dinklage, having an absolute ball) shops her for insider trading. She does porridge in the kind of prison that features tennis courts and pleasing views, only to return to a world where she has been stripped of all assets.

With no other options and no family, she doorsteps her much sat-upon former assistant Claire (Kristen Bell). From Claire’s wonky sofa-bed, Michelle soon hatches an empire-restoring plan involving chocolate brownies and girl guides.

How you get on with The Boss ultimately depends on how you get on with Melissa McCarthy. Suffice to say, if you're one of the 600,000 people who gave thumbs down to the Ghostbusters trailer, this film probably isn't for you.

The Boss began life as a McCarthy improvisation at the Groundings theatre and those origins frequently tell. The plot – will she choose business over her new adopted family – is off the cheap rack. The phrase fitfully amusing can feel generous. The direction by McCarthy's husband and writing partner Ben Falcone (What to Expect When You're Expecting) is grand, like.

Still, there’s something irrepressible about McCarthy’s shtick. Her foul-mouthed rants are always amusing, even when they’re not quite laugh-out-loud funny. There is something commendable, too, about McCarthy’s unabashed use of feminised jokes in the same marketplace where Nancy Drew was recently cancelled for “skewing too female”.

Watch as McCarthy and Kristen Bell get into a tit-slapping fight when the latter attempts to go on a date in a beige “TV-watching” jumper and an old nursing bra. We won’t see that in any other film this year. Slap away.