Warning: This story contains spoilers from Echoes. 

Playing twins is hard enough, but transforming from one character to another in real time? Now that is what we call acting. Just ask Michelle Monaghan, whose performance in a pivotal scene in Echoes’ sixth episode will leave you with your jaw stuck to the floor. 

In the new limited series, the actor plays identical twins Leni and Gina, who have secretly been switching lives for years. Clothes, jobs, kids, husbands — you name it, they share it. But Leni’s sudden disappearance from her North Carolina horse farm threatens to expose their subterfuge, especially when Detective Floss (Karen Robinson) starts questioning a frazzled Gina, who is back in town from her home in Los Angeles to help with the search. Eventually the audience learns the truth: The missing Leni is actually Gina, who ran away to escape the real Leni’s hold on both their lives and find happiness with an old flame, Dylan (Jonathan Tucker). 

In Episode 6, Floss has cornered both Leni and Gina and brought them in for questioning. But though she has her suspicions about what’s going on, it’s not until Gina physically proves just how she’s been fooling people into thinking she’s Leni that the magnitude of their deception finally hits home. 

“I was very nervous for that scene,” Monaghan tells Tudum, adding that she was worried about coming off as a caricature. Still, she understood why it was necessary. “You see the women both caught, but they're both still trying to protect themselves and each other. As Detective Floss is going back and forth, and once Dylan is brought up, Gina just realizes she has to transcend this relationship and really honor him, and she reveals the ultimate truth.”

Plus: “Blending these two women together is so fun for the audience to see. I just had to commit to it.”

And boy, does she ever. Tossing her long hair to the side, Gina starts gathering strands into Leni’s signature braid. Her gaze softens, and when she speaks, it’s with a gentle Southern twang — night and day from Gina’s harsher, brusque tones. Floss, watching this spooky spectacle, is understandably floored. “I just love Karen's reaction,” Monaghan says. “Karen Robinson carries that whole episode beautifully and it was really fun getting to work opposite her.”

But as for the most challenging part of bringing the scene to life? “I didn’t know if I could braid my hair. I was like, ‘Lord, let the hair gods be with me right now.’”

Amen.