Brad Pitt and Marion Cotillard are two World War II spies who fall in love during a daring mission in Casablanca but all it not fair in love and war 

The main tabloid talking point around Robert Zemeckis’ handsome new WWII spy romance was that our two very starry leads, Brad Pitt and Marion Cotillard, were involved in a passionate on-set affair.

In the weeks before Allied’s release, Angelina Jolie had voted for BrexPitt and the parallels with their earlier (and awful) spy romance Mr and Mrs Smith and Allied proved all too irresistible for click bait fixated hacks.

Of course, it was all about as convincing as Allied itself. Loose lips aren’t going to sink any ships here or, indeed, add a much needed spark to Pitt and Cotillard's on-screen chemistry.

He plays Max Vatan, a dashing Canadian airman and spy who meets up with Cotillard’s veteran French Resistance operative Marianne in that cinematic landmark of intrigue, elegance and romance, Casablanca. Later in the movie, there will even be a key scene which hinges on the playing - or the not playing - of a deeply symbolic song on a piano.  

This could, indeed, be the beginning of a beautiful friendship but one that may end badly. Max and Marianne pose as husband and wife as cover for their mission to assasinate a high-ranking Nazi official but when the job is done (and it's always good to see Nazis getting machine gunned to smithereens), they find themselves falling in love for real.

However, once married and domiciled in London’s choice address of Highgate, suspicions fall on Marianne and whether she is in fact a Nazi double agent (not quite sten guns in Knightsbridge but the idea of a Nazi cell in a posh London suburb in ’42 has some potential, perhaps as a prelude to Philip K Dick's The Man in The High Castle).

Marion Cotillard talks to RTÉ Entertainment about working with Brad Pitt and why she relished the role of Marriane in Allied

It is an intriguing premise and one that is handled well by screenwriter Steven Knight, who penned the superior thriller Eastern Promises and gritty urban drama Dirty Pretty Things. However, Zemeckis, who has more than proved his talent for entertainment and thrills with Back to The Future and Forest Gump, lets high gloss and FX get in the way of credibility.

It's all terribly lumnious and the staginess tends to make Allied rather too much of a homage to the kind of 1940s war flicks Zemeckis clearly and rightly adores. From the opening scene of Pitt making a daring, CGI-assisted parachute landing in the Moroccan desert to the rather too pretty war torn London, nothing looks terribly convincing.

Cotillard acts Pitt off the screen, which is no great compliment to her superb talents

Our two starry leads never seem that committed to each other either. Maybe a life of espionage makes the heart grow cold. Anyway, as spies they are both so supernaturally good looking that they would be rumbled within minutes or at least offered a modelling contract for one of those self-mockingly elaborate perfume commercials. Quite possibly set in the deserts of North Africa.

Thankfully, Jared Harris is here to lend some ballast as a stiff-upper lip British officer caught between his friendship with Vatan and his loyalty to queen and country at the most desperate time in British history. There is also an excellent appearance by Simon McBurney as a "rat catcher", feretting out German agents which adds some real chill to the overly cosy atmosphere.  

Pitt turns in a characteristically wooden performance and Cotillard acts him off the screen, which is no great compliment to her superb talents. All this and the most placid baby since Sunny in A Series of Unfortunate Events - this kid can sleep through a German bomber crash landing behind her house.

Allied is entertaining in places. With a bit more grime on the lens and a less hammy male lead (although Pitt is in with a good chance of an Oscar for best backwards chair kicking scene), it could have been a very worthy war movie. However, despite it all - and to quote a genuine wartime classic - you may find that you have something in your eye at the very end.