diff --git a/include/nn/atk.h b/include/nn/atk.h
index 53aa9f9b..3c88663c 100644
--- a/include/nn/atk.h
+++ b/include/nn/atk.h
@@ -7,6 +7,8 @@ namespace atk {
 
 class SoundArchive {
 public:
+    struct SequenceSoundInfo;
+
     const char* GetItemLabel(u32 id) const;
     u32 GetItemId(const char* label) const;
 };