diff --git a/src/wp-includes/comment-template.php b/src/wp-includes/comment-template.php
index 9f995921fc..2d5b2d3c5e 100644
--- a/src/wp-includes/comment-template.php
+++ b/src/wp-includes/comment-template.php
@@ -552,12 +552,12 @@ function get_comment_class( $class = '', $comment_id = null, $post_id = null ) {
 function get_comment_date( $format = '', $comment_ID = 0 ) {
 	$comment = get_comment( $comment_ID );
 
-	if ( '' === $format ) {
-		$date = mysql2date( get_option( 'date_format' ), $comment->comment_date );
-	} else {
-		$date = mysql2date( $format, $comment->comment_date );
+	if ( ! is_string( $format ) || '' === $format ) {
+		$format = get_option( 'date_format' );
 	}
 
+	$date = mysql2date( $format, $comment->comment_date );
+
 	/**
 	 * Filters the returned comment date.
 	 *
@@ -1046,12 +1046,12 @@ function get_comment_time( $format = '', $gmt = false, $translate = true ) {
 
 	$comment_date = $gmt ? $comment->comment_date_gmt : $comment->comment_date;
 
-	if ( '' === $format ) {
-		$date = mysql2date( get_option( 'time_format' ), $comment_date, $translate );
-	} else {
-		$date = mysql2date( $format, $comment_date, $translate );
+	if ( ! is_string( $format ) || '' === $format ) {
+		$format = get_option( 'time_format' );
 	}
 
+	$date = mysql2date( $format, $comment_date, $translate );
+
 	/**
 	 * Filters the returned comment time.
 	 *
diff --git a/src/wp-includes/general-template.php b/src/wp-includes/general-template.php
index 094e4a4062..89748f1968 100644
--- a/src/wp-includes/general-template.php
+++ b/src/wp-includes/general-template.php
@@ -2525,12 +2525,12 @@ function get_the_date( $format = '', $post = null ) {
 		return false;
 	}
 
-	if ( '' === $format ) {
-		$the_date = get_post_time( get_option( 'date_format' ), false, $post, true );
-	} else {
-		$the_date = get_post_time( $format, false, $post, true );
+	if ( ! is_string( $format ) || '' === $format ) {
+		$format = get_option( 'date_format' );
 	}
 
+	$the_date = get_post_time( $format, false, $post, true );
+
 	/**
 	 * Filters the date a post was published.
 	 *
@@ -2654,12 +2654,12 @@ function get_the_time( $format = '', $post = null ) {
 		return false;
 	}
 
-	if ( '' === $format ) {
-		$the_time = get_post_time( get_option( 'time_format' ), false, $post, true );
-	} else {
-		$the_time = get_post_time( $format, false, $post, true );
+	if ( ! is_string( $format ) || '' === $format ) {
+		$format = get_option( 'time_format' );
 	}
 
+	$the_time = get_post_time( $format, false, $post, true );
+
 	/**
 	 * Filters the time a post was written.
 	 *
diff --git a/tests/phpunit/tests/date/getCommentDate.php b/tests/phpunit/tests/date/getCommentDate.php
new file mode 100644
index 0000000000..5369d96326
--- /dev/null
+++ b/tests/phpunit/tests/date/getCommentDate.php
@@ -0,0 +1,49 @@
+<?php
+
+/**
+ * @group date
+ * @group datetime
+ * @group comment
+ */
+class Tests_Date_Get_Comment_Date extends WP_UnitTestCase {
+
+	/**
+	 * @ticket 51184
+	 */
+	function test_get_comment_date_returns_correct_time_with_comment_id() {
+		$c = self::factory()->comment->create( array( 'comment_date' => '2020-08-29 01:51:00' ) );
+
+		$this->assertEquals( 'August 29, 2020', get_comment_date( 'F j, Y', $c ) );
+	}
+
+	/**
+	 * @ticket 51184
+	 */
+	function test_get_comment_date_returns_correct_time_with_empty_format() {
+		$c = self::factory()->comment->create( array( 'comment_date' => '2020-08-29 01:51:00' ) );
+
+		$this->assertEquals( 'August 29, 2020', get_comment_date( '', $c ) );
+		$this->assertEquals( 'August 29, 2020', get_comment_date( false, $c ) );
+	}
+
+	/**
+	 * @ticket 51184
+	 */
+	function test_get_comment_time_returns_correct_time() {
+		$c = self::factory()->comment->create( array( 'comment_date' => '2020-08-29 01:51:00' ) );
+
+		$GLOBALS['comment'] = get_comment( $c );
+		$this->assertEquals( '1:51 am', get_comment_time( 'g:i a' ) );
+	}
+
+	/**
+	 * @ticket 51184
+	 */
+	function test_get_comment_time_returns_correct_time_with_empty_format() {
+		$c = self::factory()->comment->create( array( 'comment_date' => '2020-08-29 01:51:00' ) );
+
+		$GLOBALS['comment'] = get_comment( $c );
+		$this->assertEquals( '1:51 am', get_comment_time( '' ) );
+		$this->assertEquals( '1:51 am', get_comment_time( false ) );
+	}
+}
diff --git a/tests/phpunit/tests/date/getPostTime.php b/tests/phpunit/tests/date/getPostTime.php
index c28add1450..d4cd203aa6 100644
--- a/tests/phpunit/tests/date/getPostTime.php
+++ b/tests/phpunit/tests/date/getPostTime.php
@@ -10,8 +10,9 @@ class Tests_Date_Get_Post_Time extends WP_UnitTestCase {
 	/**
 	 * @ticket 28310
 	 */
-	public function test_get_post_time_with_id_returns_correct_time() {
+	public function test_get_post_time_returns_correct_time_with_post_id() {
 		$post_id = self::factory()->post->create( array( 'post_date' => '2014-03-01 16:35:00' ) );
+
 		$this->assertEquals( '16:35:00', get_post_time( 'H:i:s', false, $post_id ) );
 	}
 
@@ -28,8 +29,9 @@ class Tests_Date_Get_Post_Time extends WP_UnitTestCase {
 	/**
 	 * @ticket 28310
 	 */
-	public function test_get_post_modified_time_with_id_returns_correct_time() {
+	public function test_get_post_modified_time_returns_correct_time_with_post_id() {
 		$post_id = self::factory()->post->create( array( 'post_date' => '2014-03-01 16:35:00' ) );
+
 		$this->assertEquals( '16:35:00', get_post_modified_time( 'H:i:s', false, $post_id ) );
 	}
 
diff --git a/tests/phpunit/tests/date/getTheDate.php b/tests/phpunit/tests/date/getTheDate.php
index 03248dba5f..2e45cd9c39 100644
--- a/tests/phpunit/tests/date/getTheDate.php
+++ b/tests/phpunit/tests/date/getTheDate.php
@@ -10,8 +10,9 @@ class Tests_Date_Get_The_Date extends WP_UnitTestCase {
 	/**
 	 * @ticket 13771
 	 */
-	function test_get_the_date_with_id_returns_correct_time() {
+	function test_get_the_date_returns_correct_time_with_post_id() {
 		$post_id = self::factory()->post->create( array( 'post_date' => '2014-03-01 16:35:00' ) );
+
 		$this->assertEquals( 'March 1, 2014', get_the_date( 'F j, Y', $post_id ) );
 	}
 
@@ -25,11 +26,22 @@ class Tests_Date_Get_The_Date extends WP_UnitTestCase {
 		$this->assertFalse( get_the_date( 'F j, Y h:i:s', 9 ) );
 	}
 
+	/**
+	 * @ticket 51184
+	 */
+	function test_get_the_date_returns_correct_time_with_empty_format() {
+		$post_id = self::factory()->post->create( array( 'post_date' => '2020-08-29 01:51:00' ) );
+
+		$this->assertEquals( 'August 29, 2020', get_the_date( '', $post_id ) );
+		$this->assertEquals( 'August 29, 2020', get_the_date( false, $post_id ) );
+	}
+
 	/**
 	 * @ticket 28310
 	 */
-	function test_get_the_time_with_id_returns_correct_time() {
+	function test_get_the_time_returns_correct_time_with_post_id() {
 		$post_id = self::factory()->post->create( array( 'post_date' => '2014-03-01 16:35:00' ) );
+
 		$this->assertEquals( '16:35:00', get_the_time( 'H:i:s', $post_id ) );
 	}
 
@@ -42,4 +54,14 @@ class Tests_Date_Get_The_Date extends WP_UnitTestCase {
 		$this->assertFalse( get_the_time( '', 9 ) );
 		$this->assertFalse( get_the_time( 'h:i:s', 9 ) );
 	}
+
+	/**
+	 * @ticket 51184
+	 */
+	function test_get_the_time_returns_correct_time_with_empty_format() {
+		$post_id = self::factory()->post->create( array( 'post_date' => '2020-08-29 01:51:00' ) );
+
+		$this->assertEquals( '1:51 am', get_the_time( '', $post_id ) );
+		$this->assertEquals( '1:51 am', get_the_time( false, $post_id ) );
+	}
 }