Professor X is in a hairy situation in Wolverine film Logan

In Logan, Patrick Stewart reprises his role as Charles Xavier/Professor X, now 90 years old and battling a debilitating illness that threatens to harm others as well.

Director James Mangold wanted to focus more on the themes of family, loyalty and love for the third and final Wolverine film - the reason the sequel does not have "Wolverine" in its title.

Opening here tomorrow, Logan is set in 2029, where mutants are almost extinct and a despondent Logan/Wolverine (Hugh Jackman) is hiding.

His companions in exile are the outcast Caliban (Stephen Merchant) and an ailing Professor X, whose singular mind is plagued by worsening seizures.

But Logan's attempts to hide from the world and his legacy abruptly end when a mysterious woman appears with an urgent request - that he shepherd an extraordinary young mutant girl (Dafne Keen) to safety.

Logan must again face off against dark forces and a villain from his past on a live-or-die mission, one that will set the time-worn warrior on a path towards fulfilling his destiny.

With Jackman back again in the role that shot him to international fame, he and Stewart play out those themes in a father-son relationship, with all the attendant pride, disappointment, anger and frustration.

It is Logan who argues with him, cares for him and controls him when necessary, even as he is drinking his days away in the midst of the isolation the two find themselves in.

At the Crosby Street Hotel in New York City, Stewart, 76 - who easily looks 10 years younger and has that self-deprecating humour of most British actors - was a delight to interview.

What choices did you make in playing Charles Xavier in Logan?

I created my own backstory for Charles' appearance in the film - he is 90-plus, and his brain is no longer the fine brain of the man we have seen over the last 16 or 17 years.

What is happening inside his head has changed significantly who he is, his personality, his outlook and his behaviour.

The head is changing so much that there is hair growing out of it.Patrick Stewart on the appearance of Charles Xavier/Professor X in Logan

It seemed to us that it would be an intriguing idea to say that it also had an impact on his appearance - the head is changing so much that there is hair growing out of it.

So my brilliant make-up artist literally applied that hair.

This has never happened to me before, hair by hair (laughs), which is why it looks so authentic and convincing.

I had a week of stubble on my chin too, and I was very happy with the look.

I lost 20 pounds in weight. I did it slowly over four months, because I wanted to get as close as possible to the appearance of a 90-year-old man who is very, very ill, without make-up.

Tell us about working with Dafne Keen, the 12-year-old actress who plays X-23, a female clone of Wolverine.

It was, for me, one delight among many delights of making this movie. She is an extraordinary individual.

James and I were talking about the screenplay long before we went into production, and he said: "Oh, there is something I would like to show you."

He fired up Dafne's audition on his computer, and I promise you I had never seen anything like it from any actor at all.

Her sense of truth, spontaneity, intensity and passion as well as extraordinary look and appearance - I watched with my mouth agape.

I said, "Of course you hired her," and he said "Oh, yes."

What were the long stretches filming in the car like?

Dafne, Hugh and I went through a fairly intense couple of weeks together because we are in that miserable vehicle, just the three of us, for a long time.

The weather in Louisiana was intense, and the air conditioning in the car did not reach the back seat, which is where I was. We were in that car, on and off, 10 to 12 hours a day.

We invented word games because we had no toys.

Hugh was very good at (it), so we passed the hot and uncomfortable hours playing word games and laughing uproariously, and nobody knew what we were laughing about. It was a delightful experience.

What do you think is the message of the movie?

Fear of the "other" is what lies behind all of this, along with selfishness.

It is only by trusting ourselves and the essential goodness in most of humanity that we can banish that fear of the different, the other, the "unlike us".

The mutants in X-Men have represented that "other" all along, and it has been one of the most important aspects of this franchise for me.

I hope that from Logan, people will take away a sense of the absolute need to embrace the "other" and the different and not reject it or build walls or take away visas.