diff --git a/index.bs b/index.bs
index c714592f..ddaba046 100644
--- a/index.bs
+++ b/index.bs
@@ -7855,11 +7855,15 @@ objects.
     An ECMAScript value |V| is [=converted to an IDL value|converted=]
     to an IDL <a interface lt="Promise">Promise<var ignore>T</var></a> value as follows:
 
-    1.  Let |promise| be [=!=] <a abstract-op>Call</a>({{%Promise_resolve%}}, {{%Promise%}}, «|V|»).
+    1.  Let |realm| be the [=relevant Realm=] of the |this| value that led to the execution of this algorithm.
+    1.  Let |promise| be [=!=] <a abstract-op>Call</a>(|realm|.\[[Intrinsics]].[[{{%Promise_resolve%}}]], |realm|.\[[Intrinsics]].[[{{%Promise%}}]], «|V|»).
     1.  Return the IDL [=promise type=] value that is a reference to the
         same object as |promise|.
 </div>
 
+Issue: The relevant |this| value is not always well-defined; see
+<a href="https://github.com/heycam/webidl/issues/135">#135</a> for discussion.
+
 <p id="promise-to-es">
     The result of [=converted to an ECMAScript value|converting=]
     an IDL [=promise type=] value to an ECMAScript