diff --git a/include/boost/lambda/detail/return_type_traits.hpp b/include/boost/lambda/detail/return_type_traits.hpp
index bf2394e..d047344 100644
--- a/include/boost/lambda/detail/return_type_traits.hpp
+++ b/include/boost/lambda/detail/return_type_traits.hpp
@@ -13,6 +13,7 @@
 #define BOOST_LAMBDA_RETURN_TYPE_TRAITS_HPP
 
 #include "boost/mpl/has_xxx.hpp"
+#include <boost/type_traits/ice.hpp>
 
 #include <cstddef> // needed for the ptrdiff_t