It’s the comeback nobody saw coming — and the news that just set the entire One Chicago fandom on fire. After months of wild speculation, NBC has finally confirmed that Chicago Fire veterans Kara Killmer and Jesse Spencer are officially returning to the show for a surprise appearance in the upcoming season finale. Yes, you read that right — Sylvie Brett and Matthew Casey are back, and they’re bringing the nostalgia, emotion, and full-circle closure fans have been craving for years.

Sources close to production have revealed that both Killmer and Spencer filmed their secret cameo scenes quietly in Chicago just weeks ago under extreme secrecy. “They wanted to keep this under wraps until the very last moment,” one insider said. “Even most of the cast didn’t know until the shoot day. It was emotional — people were crying on set.” According to reports, the cameo will serve as both a farewell and a love letter to longtime fans who’ve followed Brettsey’s rollercoaster romance since the beginning.