diff --git a/core/generator.h b/core/generator.h
index a03cd4e78..842487eb2 100644
--- a/core/generator.h
+++ b/core/generator.h
@@ -44,6 +44,7 @@ class QIcon;
 namespace Okular {
 
 class BackendOpaqueAction;
+class DocumentFonts;
 class DocumentInfo;
 class DocumentObserver;
 class DocumentSynopsis;