diff --git a/cpp/src/phonenumbers/phonenumberutil.cc b/cpp/src/phonenumbers/phonenumberutil.cc
index f1442974f3..c0c9d09a04 100644
--- a/cpp/src/phonenumbers/phonenumberutil.cc
+++ b/cpp/src/phonenumbers/phonenumberutil.cc
@@ -1710,6 +1710,17 @@ void PhoneNumberUtil::FormatOutOfCountryKeepingAlphaChars(
     PrefixNumberWithCountryCallingCode(country_code, INTERNATIONAL,
                                        formatted_number);
   }
+  std::string region_code;
+  GetRegionCodeForCountryCode(country_code, &region_code);
+  // Metadata cannot be null because the country code is valid.
+  const PhoneMetadata* metadata_for_region =
+      GetMetadataForRegionOrCallingCode(country_code, region_code);
+  // Strip any extension
+  std::string extension;
+  MaybeStripExtension(formatted_number, &extension);
+  // Append the formatted extension
+  MaybeAppendFormattedExtension(number, *metadata_for_region, INTERNATIONAL,
+                                formatted_number);
 }
 
 const NumberFormat* PhoneNumberUtil::ChooseFormattingPatternForNumber(
diff --git a/cpp/test/phonenumbers/phonenumberutil_test.cc b/cpp/test/phonenumbers/phonenumberutil_test.cc
index 4f69903492..97cf1f08a4 100644
--- a/cpp/test/phonenumbers/phonenumberutil_test.cc
+++ b/cpp/test/phonenumbers/phonenumberutil_test.cc
@@ -935,6 +935,16 @@ TEST_F(PhoneNumberUtilTest, FormatOutOfCountryKeepingAlphaChars) {
                                                   &formatted_number);
   EXPECT_EQ("1 800 SIX-FLAG", formatted_number);
 
+  // Testing a number with extension.
+  formatted_number.clear();
+  PhoneNumber alpha_numeric_number_with_extn;
+  phone_util_.ParseAndKeepRawInput("800 SIX-flag ext. 1234", RegionCode::US(),
+                                   &alpha_numeric_number_with_extn);
+  // preferredExtnPrefix for US is " extn. " (in test metadata)
+  phone_util_.FormatOutOfCountryKeepingAlphaChars(
+      alpha_numeric_number_with_extn, RegionCode::AU(), &formatted_number);
+  EXPECT_EQ("0011 1 800 SIX-FLAG extn. 1234", formatted_number);
+
   // Testing that if the raw input doesn't exist, it is formatted using
   // FormatOutOfCountryCallingNumber.
   alpha_numeric_number.clear_raw_input();
diff --git a/java/libphonenumber/src/com/google/i18n/phonenumbers/PhoneNumberUtil.java b/java/libphonenumber/src/com/google/i18n/phonenumbers/PhoneNumberUtil.java
index d843bbbe9c..6d8004f182 100644
--- a/java/libphonenumber/src/com/google/i18n/phonenumbers/PhoneNumberUtil.java
+++ b/java/libphonenumber/src/com/google/i18n/phonenumbers/PhoneNumberUtil.java
@@ -1878,8 +1878,11 @@ public String formatOutOfCountryKeepingAlphaChars(PhoneNumber number,
     String regionCode = getRegionCodeForCountryCode(countryCode);
     // Metadata cannot be null because the country calling code is valid.
     PhoneMetadata metadataForRegion = getMetadataForRegionOrCallingCode(countryCode, regionCode);
-    maybeAppendFormattedExtension(number, metadataForRegion,
-                                  PhoneNumberFormat.INTERNATIONAL, formattedNumber);
+    // Strip any extension
+    maybeStripExtension(formattedNumber);
+    // Append the formatted extension
+    maybeAppendFormattedExtension(
+        number, metadataForRegion, PhoneNumberFormat.INTERNATIONAL, formattedNumber);
     if (internationalPrefixForFormatting.length() > 0) {
       formattedNumber.insert(0, " ").insert(0, countryCode).insert(0, " ")
           .insert(0, internationalPrefixForFormatting);
diff --git a/java/libphonenumber/test/com/google/i18n/phonenumbers/PhoneNumberUtilTest.java b/java/libphonenumber/test/com/google/i18n/phonenumbers/PhoneNumberUtilTest.java
index 6bdef41a7c..2b9345c4c7 100644
--- a/java/libphonenumber/test/com/google/i18n/phonenumbers/PhoneNumberUtilTest.java
+++ b/java/libphonenumber/test/com/google/i18n/phonenumbers/PhoneNumberUtilTest.java
@@ -675,7 +675,7 @@ public void testFormatOutOfCountryWithPreferredIntlPrefix() {
                  phoneUtil.formatOutOfCountryCallingNumber(IT_NUMBER, RegionCode.UZ));
   }
 
-  public void testFormatOutOfCountryKeepingAlphaChars() {
+  public void testFormatOutOfCountryKeepingAlphaChars() throws Exception {
     PhoneNumber alphaNumericNumber = new PhoneNumber();
     alphaNumericNumber.setCountryCode(1).setNationalNumber(8007493524L)
         .setRawInput("1800 six-flag");
@@ -701,6 +701,13 @@ public void testFormatOutOfCountryKeepingAlphaChars() {
     assertEquals("1 800 SIX-FLAG",
                  phoneUtil.formatOutOfCountryKeepingAlphaChars(alphaNumericNumber, RegionCode.BS));
 
+    // Testing a number with extension.
+    PhoneNumber alphaNumericNumberWithExtn =
+        phoneUtil.parseAndKeepRawInput("800 SIX-flag ext. 1234", RegionCode.US);
+    assertEquals(
+        "0011 1 800 SIX-FLAG extn. 1234",
+        phoneUtil.formatOutOfCountryKeepingAlphaChars(alphaNumericNumberWithExtn, RegionCode.AU));
+
     // Testing that if the raw input doesn't exist, it is formatted using
     // formatOutOfCountryCallingNumber.
     alphaNumericNumber.clearRawInput();
diff --git a/javascript/i18n/phonenumbers/phonenumberutil.js b/javascript/i18n/phonenumbers/phonenumberutil.js
index d6e67138ec..8812d3aa4e 100644
--- a/javascript/i18n/phonenumbers/phonenumberutil.js
+++ b/javascript/i18n/phonenumbers/phonenumberutil.js
@@ -4771,8 +4771,7 @@ i18n.phonenumbers.PhoneNumberUtil.prototype.canBeInternationallyDialled =
  */
 i18n.phonenumbers.PhoneNumberUtil.matchesEntirely = function(regex, str) {
   /** @type {Array.<string>} */
-  var matchedGroups = (typeof regex == 'string') ?
-      str.match('^(?:' + regex + ')$') : str.match(regex);
+  var matchedGroups = str.match(new RegExp('^(?:' + (typeof regex == 'string' ? regex : regex.source) + ')$', 'i'));
   if (matchedGroups && matchedGroups[0].length == str.length) {
     return true;
   }
diff --git a/pending_code_changes.txt b/pending_code_changes.txt
index 8b13789179..d67706acc0 100644
--- a/pending_code_changes.txt
+++ b/pending_code_changes.txt
@@ -1 +1,2 @@
-
+Code changes:
+ - Fixed a bug where the extension was appended twice in formatOutOfCountryKeepingAlphaChars in the Java version and updated FormatOutOfCountryKeepingAlphaChars in the C++ version to format the extension.
\ No newline at end of file