diff --git a/include/zim/item.h b/include/zim/item.h
index 07ec0607a..f1bc37047 100644
--- a/include/zim/item.h
+++ b/include/zim/item.h
@@ -91,6 +91,7 @@ namespace zim
 
 #ifdef ZIM_PRIVATE
       cluster_index_type getClusterIndex() const;
+      blob_index_type getBlobIndex() const;
 #endif
 
     private: // data
diff --git a/src/item.cpp b/src/item.cpp
index 19a95e9c5..ed65c6d24 100644
--- a/src/item.cpp
+++ b/src/item.cpp
@@ -103,3 +103,8 @@ cluster_index_type Item::getClusterIndex() const
 {
   return m_dirent->getClusterNumber().v;
 }
+
+blob_index_type Item::getBlobIndex() const
+{
+  return m_dirent->getBlobNumber().v;
+}