diff --git a/src/external_references.rs b/src/external_references.rs
index 6e8441f5..3a9eb106 100644
--- a/src/external_references.rs
+++ b/src/external_references.rs
@@ -11,6 +11,7 @@ use crate::NamedGetterCallback;
 use crate::NamedSetterCallback;
 use crate::PropertyEnumeratorCallback;
 use std::ffi::c_void;
+use std::fmt::Debug;
 
 #[derive(Clone, Copy)]
 pub union ExternalReference<'s> {
@@ -26,6 +27,13 @@ pub union ExternalReference<'s> {
   pub pointer: *mut c_void,
 }
 
+impl<'s> Debug for ExternalReference<'s> {
+  fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+    // SAFETY: All union fields are the same size
+    unsafe { (self.pointer).fmt(f) }
+  }
+}
+
 #[derive(Debug, Clone)]
 pub struct ExternalReferences {
   null_terminated: Vec<intptr_t>,
diff --git a/tests/test_api.rs b/tests/test_api.rs
index fd9886ea..47cadd07 100644
--- a/tests/test_api.rs
+++ b/tests/test_api.rs
@@ -5309,7 +5309,7 @@ fn external_references() {
   let external_ptr = Box::into_raw(vec![0_u8, 1, 2, 3, 4].into_boxed_slice())
     as *mut [u8] as *mut c_void;
   // Push them to the external reference table.
-  let refs = v8::ExternalReferences::new(&[
+  let refs = [
     v8::ExternalReference {
       function: fn_callback.map_fn_to(),
     },
@@ -5319,7 +5319,10 @@ fn external_references() {
     v8::ExternalReference {
       pointer: external_ptr,
     },
-  ]);
+  ];
+  // Exercise the Debug impl
+  println!("{refs:?}");
+  let refs = v8::ExternalReferences::new(&refs);
   // TODO(piscisaureus): leaking the `ExternalReferences` collection shouldn't
   // be necessary. The reference needs to remain valid for the lifetime of the
   // `SnapshotCreator` or `Isolate` that uses it, which would be the case here