Michael Fassbender’s grunts in the gym

Michael Fassbender grunts when he works out.

The 39-year-old actor thinks he probably infuriated his co-star Marion Cotillard when they shot the reboot of ‘Macbeth’ last year because he’d always rock up to set an hour before his shooting cue to work up a sweat in the gym and was often "vocal" doing so.

He explained: "I would turn up an hour and a half early before make up call and she probably caught the tail end of my workout. And yeah, I am an extremely vocal worker-outer. I am the Monica Seles [a grunting tennis player] of the gym."

But one person who won’t be complaining about his obscure noises on set is his girlfriend Alicia Vikander, whom he’s been dating since 2014, because she’s used to it after working with him on the 2016 blockbuster ‘The Light Between Oceans’.

Speaking to The Times newspaper, he said: "I think chemistry is chemistry: it’s either there or it’s not. We just work really well together – she’s a fantastic actor and she brings it on the day of shooting and you have to try and keep up. It’s a sparring, dancing thing – you’re supporting each other, provoking each other."

And the couple are no doubt looking forward to a quiet festive season over the next few weeks as they’re planning to spend Christmas Day (25.12.16) together this year.

Asked if they’ll celebrate the occasion together, Michael said: "Yep."

But when pressed on whether he’s planning to jet across to Alicia’s native Sweden or whether they’ll celebrate in his hometown in Ireland, he said: "I’m not going to tell you!"