diff --git a/xs/xsp/my.map b/xs/xsp/my.map
index 5f87f51c2c..43848e3d63 100644
--- a/xs/xsp/my.map
+++ b/xs/xsp/my.map
@@ -254,7 +254,7 @@ INPUT
 T_STD_STRING
     {
       size_t len;
-      const char * c = SvPV($arg, len);
+      const char * c = SvPVutf8($arg, len);
       $var = std::string(c, len);
     }