diff --git a/include/boost/exception/exception.hpp b/include/boost/exception/exception.hpp
index 96cd893..4d1a0ad 100644
--- a/include/boost/exception/exception.hpp
+++ b/include/boost/exception/exception.hpp
@@ -412,16 +412,17 @@ boost
             public T,
             public clone_base
             {
-            public:
-
-            explicit
-            clone_impl( T const & x ):
+            struct clone_tag { };
+            clone_impl( clone_impl const & x, clone_tag ):
                 T(x)
                 {
                 copy_boost_exception(this,&x);
                 }
 
-            clone_impl( clone_impl const & x ):
+            public:
+
+            explicit
+            clone_impl( T const & x ):
                 T(x)
                 {
                 copy_boost_exception(this,&x);
@@ -436,7 +437,7 @@ boost
             clone_base const *
             clone() const
                 {
-                return new clone_impl(*this);
+                return new clone_impl(*this,clone_tag());
                 }
 
             void