Sexual tension 'off the charts'
When it came out in July last year, the movie's first trailer was akin to foreplay.
Set to an achingly sensuous remix of Beyonce's Crazy In Love, it revealed such a brief yet seductive taste of the Fifty Shades universe I was instantly fearful the actual movie wouldn't be able to match up.
I'm relieved to report I left the two-hour session satisfied.
And if you happen to be a Twihard, you'll get extra pleasure out of it.
While devouring the book trilogy before the movie was cast, I was imagining Robert Pattinson and Emma Roberts - who were both rumoured to be involved - in the lead roles.
However, Johnson and Dornan came out of nowhere and proved beyond a doubt they are more than just pretty (empty) vessels.
Johnson gives an especially beguiling performance - the camera loves every inch of her face and body, and those blue-green eyes are everything.
As for Dornan, somebody just give him the 2015 Sexiest Man Alive title already!
Here's the funny thing about this pairing.
On all the occasions they've had to appear together to promote the movie, they have looked like they'd rather be anywhere but standing next to each other. Yet, on screen, the sexual tension is off the charts.
Either these two boast Oscar-worthy acting chops, or they had a "thing" in real life which ended badly.
Whatever the case, Johnson and Dornan committed where it mattered.
She's totally nude when it's called for, while he's almost there.
Even though an arsenal of apparatus like floggers, ropes, handcuffs and belts from Christian's "red room of pain" make cameos, the supposedly controversial sex scenes are thankfully far from graphic (which explains why the film was passed uncut), and deliver the right amount of eroticism.
If anyone wants to complain about sexual violence and the glamorising of domestic abuse, Hollywood has churned out more hardcore trash than this.
Essentially, this is an adult movie with adult themes.
It explores and unravels a complicated, disturbing dominant-submissive relationship involving issues of control, trust, rewards and punishments, where there is no black and white, only - you guessed it - shades of grey.
Most women can't possibly relate to the BDSM aspect, but I suspect we can identify with the desire to fix dark, dangerous, damaged men.
Yet, a big part of Fifty Shades is also pure hearts-and-flowers female fantasy, the swoon-worthy romance just as palpable as the heat.
Taylor-Johnson has likened this gig to "walking a knife edge", but she nailed it.
The abrupt ending may come across as anticlimactic, but it will whet fans' appetites for the sequels to come. The only torture here is in the waiting.