diff --git a/Userland/Libraries/LibJS/Runtime/RegExpPrototype.cpp b/Userland/Libraries/LibJS/Runtime/RegExpPrototype.cpp
index 29d20760d0..14e7880547 100644
--- a/Userland/Libraries/LibJS/Runtime/RegExpPrototype.cpp
+++ b/Userland/Libraries/LibJS/Runtime/RegExpPrototype.cpp
@@ -399,7 +399,14 @@ JS_DEFINE_NATIVE_FUNCTION(RegExpPrototype::symbol_replace)
             if (vm.exception())
                 return {};
         } else {
-            replacement = get_substitution(global_object, matched, string, position, captures, named_captures, replace_value);
+            auto named_captures_object = js_undefined();
+            if (!named_captures.is_undefined()) {
+                named_captures_object = named_captures.to_object(global_object);
+                if (vm.exception())
+                    return {};
+            }
+
+            replacement = get_substitution(global_object, matched, string, position, captures, named_captures_object, replace_value);
             if (vm.exception())
                 return {};
         }
diff --git a/Userland/Libraries/LibJS/Tests/builtins/String/String.prototype.replace.js b/Userland/Libraries/LibJS/Tests/builtins/String/String.prototype.replace.js
index a570a68ad0..16d481c9f8 100644
--- a/Userland/Libraries/LibJS/Tests/builtins/String/String.prototype.replace.js
+++ b/Userland/Libraries/LibJS/Tests/builtins/String/String.prototype.replace.js
@@ -139,3 +139,19 @@ test("replacement with substitution", () => {
     expect("abc".replace(/(?<val1>a)b(?<val2>c)/, "$<val2>")).toBe("c");
     expect("abc".replace(/(?<val1>a)b(?<val2>c)/, "$<val2>b$<val1>")).toBe("cba");
 });
+
+test("replacement with substitution and 'groups' coerced to an object", () => {
+    var r = /./;
+    var coercibleValue = {
+        length: 1,
+        0: "b",
+        index: 1,
+        groups: "123",
+    };
+
+    r.exec = function () {
+        return coercibleValue;
+    };
+
+    expect(r[Symbol.replace]("ab", "[$<length>]")).toBe("a[3]");
+});