Romance or showmance? That, to mangle the words of William Shakespeare, is the question circling around veteran Irish actor Liam Neeson and his co-star Pamela Anderson – who, if you believe the Hollywood gossip mill, became a couple after bonding on the set of their latest film.

And ever since I photographed the pair for The Mail on Sunday’s YOU magazine in New York a few weeks ago, I have constantly been asked if the romance is real.

My reply has always been the same: that it was clear to me that Liam and Pamela shared amazing chemistry.

At that stage, I hadn’t heard any rumours from the set of their reboot of the comedy crime movie The Naked Gun, but I did notice how relaxed they were in each other’s company and how much fun they had together.

I’ve photographed a lot of celebrities over many years and the atmosphere before and during a shoot can often be tense – particularly when more than one person is involved and there’s extra scope for disagreements and unforeseen problems to crop up.

So I wasn’t really sure how this shoot in the famous Highline studio in New York’s fashionable Meatpacking District would go. I did notice that Pamela, 58, arrived looking utterly fabulous in white sun hat, white dress and sunglasses – and noted to myself it was almost as if she was expecting the paparazzi to be waiting outside.

Liam, 73, arrived separately a short time afterwards and both promptly disappeared into their own dressing rooms for make-up and styling, as you’d expect from professionals.

The first time I saw them together was the moment they emerged into the studio lights. I could immediately tell that they got on like a house on fire.

They were charming, friendly and tactile – almost touchy-feely with each other.

Neither of them seemed at all nervous. In fact, they were very cooperative and seemed at ease physically – all laughs and smiles and happy to drape themselves in each other’s arms.

I’d brought along some old-style cameras and suggested they might want to take pictures of each other. Immediately, Pamela threw herself on the floor and Liam crouched over her in an imitation of the famous poster for the Swinging Sixties film Blow-Up, which they both thought was hilarious, particularly as the crime theme gelled well with the movie they were there to publicise.

Through my camera lens I could see the way they looked and smiled at one another and it was clear they were really enjoying themselves. That made life easy for me as a photographer.

The atmosphere of the shoot was absolutely buzzing. The publicity people from the studio were laughing and joking. They loved the way the pictures were coming out. When I got home that night and told my wife how much fun the job had been, she mentioned she’d just read in the gossip columns that Liam and Pamela were apparently dating.

Now you don’t get to be married to a showbiz photographer for years without developing a healthy dose of cynicism.

The next thing she said to me was: ‘But this is just business, right?

‘Rumours of off-screen romance are the oldest publicity trick in the world…’

Of course, she’s right. Ever since Humphrey Bogart and Lauren Bacall’s sizzling on-screen chemistry was revealed as a real-life love match, talk of steamy goings-on among the stars has all but guaranteed a healthy burst of publicity for any film.

Indeed, the early reviews for The Naked Gun stress the chemistry between Neeson and Anderson’s characters is the most enjoyable feature of the movie. But for every Bogey and Bacall there’s a couple that just played up to the cameras for publicity. So where does this leave Pam and Liam? Are they really in a relationship, or are they a pair of great actors having a wonderful time in the limelight – and sharing a big old laugh at our expense?

I really can’t say. But I do know their friendship seemed both natural and fun.

I was thrilled to capture their rapport and energy. It’s every photographer’s dream to collaborate with such fantastic talent to produce images that have really resonated with fans and the public alike.

I got an amazing response on Instagram from hundreds of people . . . even Dannii Minogue commented how much she liked the photos! I love that.

My 90-minute shoot with them was the most enjoyable I’ve done all year.

They looked fantastic together and I am so grateful to have had the opportunity.