James McAvoy is busy working on the upcoming X-Men film Dark Phoenix but took time out to appear as a guest on The Late Show With Stephen Colbert on 19 July (Wednesday).

The actor, who plays Professor X in the franchise, spoke at length on the show about meeting a certain celebrity while filming in Montreal, Canada last month.

The talk show host brought up a photo that McAvoy shared on his Instagram account which showed the cast of the film along with the Canadian Prime Minister Justin Trudeau.

"Just met 'the dude,'" he captioned the post. "Thank you Canada for such a progressive, impressive and somewhat suggestive real life superhero."

Just met "the dude".thank you Canada for such a progressive,impressive and somewhat suggestive real life superhero. #justintrudeau #xmen #somanyopenmouths #priministerinatshirt

A post shared by James Mcavoy (@jamesmcavoyrealdeal) on

"The question this photo raises is," Colbert began, "What is Justin Trudeau's X-Men mutant power... other than making us wish we lived in Canada."

The Split actor thought for a moment before responding: "Good hair."

"All of your hair went to him," Colbert interjected, pointing to the actor's shaven head. "He's the Rogue of hair styles."

On the subject of hair and the lack of it (in McAvoy's case), the Atomic Blonde star was asked if he does anything to maintain his shaven scalp.

"A little bit of moisturizer," he offered with a shake of his head, before revealing that at times he also used a tinted day cream to make himself look less like a neo-Nazi.

"Sometimes, when I'm going out for dinner, I feel a bit self-conscious about it," he added. "It's slightly off-putting for people who have an aversion to skin-heads.

"So I put a little bit of tinted day cream and suddenly people are like, 'Oh! You're like Patrick Stewart... you're friendly'."

X-Men: Dark Phoenix is set to release in cinemas across the US and UK on 2 November, 2018.