The term ‘star vehicle’ is bandied around perhaps a pinch too often in this digital age of insta-celebrity and influencer fandom.

Yet there’s little doubt that it is exactly what 1992’s The Bodyguard proved to be, with its art-imitating-life framing of the late, great Whitney Houston as a headline-grabbing pop-star in need of protection from a dangerous stalker, as she swirls her way through an album launch and Oscar nomination.

Its transplanting from screen to stage is unsurprisingly effortless – the film’s titanic, record-breaking soundtrack did all of the leg-work then (courtesy of Houston’s powerhouse lungs), and continues, for the most part, to do so here. As with its cinematic predecessor, the central tale and formula of Bodyguard is predictable to the point of almost being rote; rich, entitled yet well-meaning megastar has gruff, handsome protector type thrust upon her, and the initial animosity and frostiness between the two eventually blossoms into a romance that will have everyone reaching for the hankies over come the finale.

It doesn’t even attempt to break the mould or really flesh out too far beyond the blueprint of the film, but nor does it really need to. It’s accessible, effective and entertaining, pitched perfectly for the hen do and girls night out crowds (if you’ll forgive some over-generalisation). Director Thea Sharrock and design team Tim Hatley, Mark Henderson, Duncan McLean and Richard Brooker certainly put on a show – from pillars of flames erupting from the front of the stage to expansive projections and rapid edits selling the pop concert vibes (if slightly by way of The X Factor/Britain’s Got Talent), Bodyguard makes good on its Hollywood and pop concert trappings, even if there are some noticeable cut corners on the extravagance this time round. It even gets some punchy moments of shock and brief horror neatly tucked in throughout for good measure, too.

“A romance that comes across now a little formulaic, though it is undoubtedly what the vast majority of the audience will be there to see…”

But it is, first and foremost, a love story, and there’s no shaking that the raw, forbidden trespass of passion and profession between Houston and Kevin Costner felt a lot more daring back in the early 90s. It’s a romance that comes across now a little formulaic, though it is undoubtedly what the vast majority of the audience will be there to see (along with, naturally, a Whitney-esque belt or two).

It feels oddly dated elsewhere, too. See the clumsily regressive handling of its LGBT characters in particular – cookie cutter cliches of campy cattiness, for the most part.

To put it plainly, we’ve seen it all before.

But, again, with The Bodyguard, that’s sort of the point.

So all eyes (and ears) tend to fall on appraising how good each individual production’s Rachel Marron is. The separation between character and actress in the film was practically non-existent, so it’s unsurprising that, outside of its West End debut (where musical theatre goddess Heather Headley first steered the ship), touring productions of Bodyguard have tried to inject some of that Whitney duality synergy by having ‘IRL’ pop-stars take on the central role. From Beverley Knight to Alexandra Burke, what has been fairly consistent is the calibre of vocal chops they’ve hung pretty much the entirety of the show on.

On paper, hiring Pussycat Dolls star Melody Thornton for this latest tour makes a lot of creative and commercial sense. Actual proven chart-topper and pop star to portray the fictional chart-topper and pop star? Check. Someone who knows the show and has already portrayed the role before? Check.

A vocalist and performer with the vocal and acting range to carry such a monumental show with such colossal sings? Well, let’s explore that for a moment…

It’s often said that the measure of a good musical theatre performer, or indeed any performer, is the degree of confidence that they are able to imbue into their audience. A stalwart of the boards will break down the barriers of apprehension and suspension of disbelief, and assuage any doubts about any of the big numbers or challenging choreography ahead.

For the first half of the performance reviewed, it has to be said that Thornton didn’t quite deliver on this. There’s no doubting that she possesses a strong, soulful voice, but there was a reticence and restraint to her performance that made each inevitable big ballad an uncertain thing. It isn’t great to be watching The Bodyguard and having trepidation over whether or not your Rachel Marron is going to go for the big notes or play it safe.

It isn’t just the singing, either – supposedly high-energy, performative showstoppers such as ‘Million Dollar Bill’ and ‘How Will I Know’, despite being a touch over-choreographed here, still felt strangely languid and unenergised. The fantastic swing and ensemble gave it their all, but Thornton seemed to be holding back.

“…spinning, twirling and bopping her way through a kinetic, buoyant curtain call, you can’t help but ask ‘where was this Rachael Marron for so much of the show?’”

Now, with all that being said, for what can only be surmised by this particular writer as Thornton perhaps pacing herself and not wishing to over-exert ahead of the big tentpole moments that close out the show, she positively came alive for Act II, giving searing renditions of ‘One Moment in Time’ and, crucially, the iconic ‘I Will Always Love You’. And spinning, twirling and bopping her way through a kinetic, buoyant curtain call, you can’t help but ask ‘where was this Rachael Marron for so much of the show?’ By close, it becomes patently obvious that Thornton has ‘it’, and is a great fit for the role, but it’s perhaps debatable whether the actualisation of this comes a little too late in the day.

Around her, Ayden Callaghan is solid as the gruff, no-nonsense Frank. It’s a fairly thankless and slightly under-written part, plastering blanket stoicism over any major development or depth, but Callaghan is a suitably brooding and handsome foil. He gives good deadpan, and certainly offers up the physicality required for the role. The talented Emily-Mae, meanwhile, continues a long-running Bodyguard trend of having the role of Rachel’s sister Nicki threaten to steal the whole show from under her.

And there’s not really much more than that to The Bodyguard. It’s consummate popcorn entertainment pushed through the mould of the musical: light, predictable, ‘poppy’ fun. Sure, it benefits immensely from having some of the best pop classics of the past few decades as its soundboard, and it looks and feels like a quality piece of theatre craft throughout. But with cookie cutter characters and little invention or embellishment beyond what was already a pretty formulaic script, this is a show which lives or dies by its casting.

On current form? It’s still likely a must-see for those who are ardent Houston enthusiasts or admirers of the film, of which there are countless. But even on those grounds, it’s a somewhat inconsistent outing this time round, with plenty of strong, belting highs, but more than a few languid, breathing lows, too.

For everyone else? If unpretentious nights of jukebox fun are your thing, then go for the tunes and the unapologetic, frothy entertainment factor of it all. Stay for a central performance that, whilst initially hesitant and restrained, and not the most dynamic or instinctive of acting turns, eventually blossoms into something far stronger and more affecting.

It takes some getting there, and it isn’t a journey without some hesitation and doubts, but come the curtain call, there’ll be few left in the auditorium not bopping along to Thornton, and welcoming her as a (mostly) fully-fledged Queen of the Night.