diff --git a/taglib/asf/asfattribute.cpp b/taglib/asf/asfattribute.cpp
index 116bfe21..7a40bea3 100644
--- a/taglib/asf/asfattribute.cpp
+++ b/taglib/asf/asfattribute.cpp
@@ -72,10 +72,12 @@ ASF::Attribute::Attribute(const ASF::Attribute &other)
 
 ASF::Attribute &ASF::Attribute::operator=(const ASF::Attribute &other)
 {
-  if(d->deref())
-    delete d;
-  d = other.d;
-  d->ref();
+  if(&other != this) {
+    if(d->deref())
+      delete d;
+    d = other.d;
+    d->ref();
+  }
   return *this;
 }