Sarah Hyland is about to blow us all away as the grown-up version of the Seelie Queen on Freeform's Shadowhunters. But did you know she has her Halloween costume to thank for the part?

Showrunner Matt Hastings explained that Hyland showed him a photo of her Halloween costume last year — which just so happened to be a fairy costume — and that pretty much cemented her in his mind as the Seelie Queen.

Shadowhunters: Sarah Hyland to Guest Star as Seelie Queen

"I immediately sent it to [Todd Slavkin and Darren Swimmer], and I was like, 'We found the Seelie Queen! She's here on our set!'" Hastings says.

Dominic Sherwood was thrilled to see Hyland take on this character too, especially since it's a role so different from the one she's used to playing. "It's really nice to see Sarah delve so deep into a character for the first time in almost 10 years because she's been on [Modern Family] for such a long time. It's been the same character, so for the first time she's got to really stray away from that and play someone very different."

Shadowhunters airs Mondays at 8/7c on Freeform.