diff --git a/src/wp-includes/comment.php b/src/wp-includes/comment.php
index b9d084c997..41a2260503 100644
--- a/src/wp-includes/comment.php
+++ b/src/wp-includes/comment.php
@@ -2094,7 +2094,24 @@ function wp_update_comment_count_now($post_id) {
 		return false;
 
 	$old = (int) $post->comment_count;
-	$new = (int) $wpdb->get_var( $wpdb->prepare("SELECT COUNT(*) FROM $wpdb->comments WHERE comment_post_ID = %d AND comment_approved = '1'", $post_id) );
+
+	/**
+	 * Filters a post's comment count before it is updated in the database.
+	 *
+	 * @since 4.5.0
+	 *
+	 * @param int $new     The new comment count. Default null.
+	 * @param int $old     The old comment count.
+	 * @param int $post_id Post ID.
+	 */
+	$new = apply_filters( 'pre_wp_update_comment_count_now', null, $old, $post_id );
+
+	if ( is_null( $new ) ) {
+		$new = (int) $wpdb->get_var( $wpdb->prepare( "SELECT COUNT(*) FROM $wpdb->comments WHERE comment_post_ID = %d AND comment_approved = '1'", $post_id ) );
+	} else {
+		$new = (int) $new;
+	}
+
 	$wpdb->update( $wpdb->posts, array('comment_count' => $new), array('ID' => $post_id) );
 
 	clean_post_cache( $post );
diff --git a/tests/phpunit/tests/comment/wpUpdateCommentCountNow.php b/tests/phpunit/tests/comment/wpUpdateCommentCountNow.php
new file mode 100644
index 0000000000..7e3ed2bcae
--- /dev/null
+++ b/tests/phpunit/tests/comment/wpUpdateCommentCountNow.php
@@ -0,0 +1,52 @@
+<?php
+
+/**
+ * @group  comment
+ * @covers wp_update_comment_count_now
+ */
+class Tests_Update_Comment_Count_Now extends WP_UnitTestCase {
+	public function _return_100() {
+		return 100;
+	}
+
+	public function test_invalid_post_bails_early() {
+		$this->assertFalse( wp_update_comment_count_now( 100 ) );
+		$this->assertFalse( wp_update_comment_count_now( null ) );
+		$this->assertFalse( wp_update_comment_count_now( 0 ) );
+	}
+
+	public function test_regular_post_updates_comment_count() {
+		global $wpdb;
+
+		$post_id = self::factory()->post->create();
+
+		self::factory()->comment->create_post_comments( $post_id, 1 );
+		$this->assertSame( '1', get_comments_number( $post_id ) );
+
+		$num_queries = $wpdb->num_queries;
+		$this->assertTrue( wp_update_comment_count_now( $post_id ) );
+		$this->assertSame( $num_queries + 2, $wpdb->num_queries );
+
+		$this->assertSame( '1', get_comments_number( $post_id ) );
+	}
+
+	public function test_using_filter_adjusts_comment_count_without_an_additional_database_query() {
+		global $wpdb;
+
+		add_filter( 'pre_wp_update_comment_count_now', array( $this, '_return_100' ) );
+
+		$post_id = self::factory()->post->create();
+
+		self::factory()->comment->create_post_comments( $post_id, 1 );
+		$this->assertSame( '100', get_comments_number( $post_id ) );
+
+		$num_queries = $wpdb->num_queries;
+		$this->assertTrue( wp_update_comment_count_now( $post_id ) );
+		// Only one query is made instead of two.
+		$this->assertSame( $num_queries + 1, $wpdb->num_queries );
+
+		$this->assertSame( '100', get_comments_number( $post_id ) );
+
+		remove_filter( 'pre_wp_update_comment_count_now', array( $this, '_return_100' ) );
+	}
+}