Patrick Stewart keeps a bag of James McAvoy's hair in his safe.
The 75-year-old bald actor portrays Professor Charles Xavier in the X-Men franchise, the same character the 37-year-old Scottish hunk portrays as a younger man in other films in the series.
And when James decided to shave his head for the upcoming X-Men: Apocalypse, he couldn't resist giving Patrick a call - only for the veteran star to make a bizarre request.
James said "When we finally shaved it off we decided to FaceTime Patrick Stewart so he could pass on the baldy baton.
"We thought it was funny when he asked if he could have some of the hair, but it turns out the director bagged it up for him and he now has all my hair at home in a safe."
However, James - who has a five-year-old son Brendon with wife Anne-Marie Duff - admits he isn't impressed by Patrick's bizarre souvenir.
He added to talk show host Graham Norton: "[It] is kind of creepy."
And it seems the actor's gesture was in vain as producers were furious with him for chopping off his locks.
He admitted: "I shaved it months before to see what it would look like and turned up on the shoot with about two month's growth and they were like, 'What have you done?' and I had to have the first of 17-hour hair extensions sessions."
Though James' co-star in the series, Jennifer Lawrence, previously admitted the latest movie in the saga will mark her last outing as Mystique, the actor will be back for more X-Men movies.
He said in the interview, which airs in the UK on Friday: "If they write good stuff for us, if schedules work out and they pay enough money I am sure we'll still keep doing it."