KJ Apa Broke His Hand Filming the Riverdale Finale

05/11/2017 09:37 pm EDT

Spoilers ahead for "The Sweet Hereafter," tonight's season finale of Riverdale.

When you see Archie Andrews wearing a cast in the second half of tonight's Riverdale, that's not just Archie: series star KJ Apa actually broke his hand while performing a scene in which his character beats desperately at the icy surface of Sweetwater River.

"In a weird way, and I told this to KJ, the second we knew that Archie was going to be punching through ice, I literally said, 'now guys, KJ is such a committed actor, he's so method, he's so in this character and passionate, you have to make sure he doesn't hurt this hand.' So when at the end of that day I got a phone call that KJ had maybe broken his hand, I was like 'Yup,'" showrunner Roberto Aguirre-Sacasa told ComicBook.com. "He puts it all out there for the screen, that's for sure."

Last chance to turn back before major finale spoilers.

In the scene, pictured in several of the promotional images and trailers for the finale, Archie desperately tries to break the ice in time to save Cheryl Blossom, who is trapped underneath.

"I think for me, that moment — that's so visceral, and so good," showrunner Roberto Aguirre-Sacasa said of the scene. "You know, KJ broke his hand doing that scene. That's why he has a cast and his hand is covered by a jacket in a lot of scenes in a weird way. For me, that moment is all about, if Archie hadn't been there, they would not have been able to save Cheryl. Only Archie could have done that, and that really does speak to him being a hero."

That's going to be a theme that they explore going into Riverdale's second season -- but more on that later tonight.

More Riverdale news:

• Riverdale's Cheryl Blossom Returns to Sweetwater River in Season Finale Poster
• Archie Performs With Josie And The Pussycats In Riverdale Season Finale Clip
• How Will Incest Revelation Impact Riverdale?
• Riverdale: The Movies That Inspired Season 1

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