A small Glass Onion detail you probably missed gives away the big twist

A small Glass Onion: A Knives Out mystery detail gives away the big twist – and it was right in front of our noses all along. A warning that the below contains major Glass Onion spoilers! Turn back now if you haven't seen the movie yet! 

The film sees Daniel Craig's Benoit Blanc return to investigate another murder mystery, this time in the luxurious home of tech billionaire Miles Bron (Edward Norton). The star-studded cast includes Jessica Henwick, Dave Bautista, Kate Hudson, Kathryn Hahn, Madelyn Cline, Leslie Odom Jr., and Janelle Monáe. Rian Johnson also returns to direct. 

Around halfway through the film, it's revealed that Monáe's character isn't Bron's former business partner Andi after all, but is instead her twin sister Helen. Andi is actually dead, and Helen believes she was murdered. After seeking help from Blanc, he suggests she attends Bron's private island gathering to discover the truth, all the while in disguise as her sister Andi. 

One easily missed detail, though, gives the whole game away. "Helen's wig is something Rian and I talked about. When she's acting as Andi, and nobody knows it's her, the parting of her hair is on the opposite side," Monáe told Variety, adding: "The idea is that she is a mirror image of her sister."

There's even a slight difference between Andi and Helen's eyebrows. "If you're Helen, pretending to be Andi, they needed to be darker and thicker," Monáe said. "But if you're Andi, they needed to be well-groomed."

Johnson has previously revealed that he was uncertain on including the twin twist. "By the process, I was dragged kicking and screaming to identical twins," he explained. "I didn't want to do it, it seemed like a horrible trope, and just, 'Will the audience ever forgive me for this?' But I think we get away with it because it's not like a reveal at the end of 'Aha! It was a twin!' It's a complication in the middle that leads to a deepening of the stakes and the story. So I think that's why we get away with it."

Glass Onion is streaming on Netflix now. If you're up to speed on the movie, check out our spoilery guide to the Glass Onion ending explained and all the cameos. You can also fill out your watchlist with our guide to the best Netflix movies streaming now.