But at the end of the day acting skills are required: this isn’t an inept or embarrassing performance from Cheryl. She struggles to project times, and the shouty bits feel a bit forced. But she nails her lines, has good comic timing, and generally does her bit supporting the architecture of Robins’s play.
Actually it’s no fright night in that respect. She proves a class act and - whisper it - is even the most understated player on stage.
But is Cheryl any good? Actually, yes: certainly good enough to bring a new crowd to this superior, remorselessly effective spine-chiller.
Admittedly, sometimes you stop noticing her genuine emotional range or her slightly overemphatic gestures and simply gawp. Those dimples, those empathetic doe eyes, that nutcracker Geordie accent… Blimey, it’s really her! A sensational event, in every sense. As her own X Factor moment, it is respectable enough for a first go, if blunt-edged: big on volume and sudden, thunderous anger.
As for Cheryl, it's safe to say she puts in an assured debut – sure, sometimes intonation wavers, while her angry outburst can occasionally feel unexpected and one-note (then again, so do most outbursts from those suffering from sleep-deprivation). For the most part, it'll be a turn that few critics will find major fault with.
You can practically hear the critics sharpening their fangs – but to get straight to the point: hers is not the worst performance the West End has seen. It’s not even the worst performance in the West End right now. In fact, there are many moments when it’s not the worst performance on stage. Quite often, she appears completely at home, and her carefully restrained anxiety that there’s a ghost haunting her baby is the most captivating thing about the show.
Cheryl proves herself more than able to ride the emotional rollercoaster.