diff --git a/headers/private/kernel/user_debugger.h b/headers/private/kernel/user_debugger.h
index 4218f5506e..903d9323d4 100644
--- a/headers/private/kernel/user_debugger.h
+++ b/headers/private/kernel/user_debugger.h
@@ -21,6 +21,7 @@
 
 
 struct function_profile_info;
+struct thread;
 
 // Team related debugging data.
 //