diff --git a/lib/Models/ModelValidator.php b/lib/Models/ModelValidator.php
index 0593df90c3..389dd2d7a6 100644
--- a/lib/Models/ModelValidator.php
+++ b/lib/Models/ModelValidator.php
@@ -2,6 +2,8 @@
 
 namespace MailPoet\Models;
 
+use MailPoet\Util\Helpers;
+
 if(!defined('ABSPATH')) exit;
 
 class ModelValidator extends \Sudzy\Engine {
@@ -35,9 +37,11 @@ class ModelValidator extends \Sudzy\Engine {
   }
 
   function validateRenderedNewsletterBody($newsletter_body) {
-    $newsletter_body = (!is_serialized($newsletter_body)) ?
-      $newsletter_body :
-      unserialize($newsletter_body);
+    if(is_serialized($newsletter_body)) {
+      $newsletter_body = unserialize($newsletter_body);
+    } else if(Helpers::isJson($newsletter_body)) {
+      $newsletter_body = json_decode($newsletter_body, true);
+    }
     return (is_null($newsletter_body) || (is_array($newsletter_body) && !empty($newsletter_body['html']) && !empty($newsletter_body['text'])));
   }
 }
\ No newline at end of file
diff --git a/lib/Models/SendingQueue.php b/lib/Models/SendingQueue.php
index 39073cce1d..8b3c9fb279 100644
--- a/lib/Models/SendingQueue.php
+++ b/lib/Models/SendingQueue.php
@@ -1,6 +1,7 @@
 <?php
 namespace MailPoet\Models;
 
+use MailPoet\Util\Helpers;
 use MailPoet\WP\Emoji;
 
 if(!defined('ABSPATH')) exit;
@@ -56,10 +57,10 @@ class SendingQueue extends Model {
     if(!is_serialized($this->subscribers) && !is_null($this->subscribers)) {
       $this->set('subscribers', serialize($this->subscribers));
     }
-    if(!is_serialized($this->newsletter_rendered_body) && !is_null($this->newsletter_rendered_body)) {
+    if(!Helpers::isJson($this->newsletter_rendered_body) && !is_null($this->newsletter_rendered_body)) {
       $this->set(
         'newsletter_rendered_body',
-        serialize($this->encodeEmojisInBody($this->newsletter_rendered_body))
+        json_encode($this->encodeEmojisInBody($this->newsletter_rendered_body))
       );
     }
     // set the default priority to medium
@@ -84,9 +85,7 @@ class SendingQueue extends Model {
   }
 
   function getNewsletterRenderedBody($type = false) {
-    $rendered_newsletter = (!is_serialized($this->newsletter_rendered_body)) ?
-      $this->newsletter_rendered_body :
-      $this->decodeEmojisInBody(unserialize($this->newsletter_rendered_body));
+    $rendered_newsletter = $this->decodeRenderedNewsletterBodyObject($this->newsletter_rendered_body);
     return ($type && !empty($rendered_newsletter[$type])) ?
       $rendered_newsletter[$type] :
       $rendered_newsletter;
@@ -165,4 +164,15 @@ class SendingQueue extends Model {
     }
     return $this->save();
   }
+
+  private function decodeRenderedNewsletterBodyObject($rendered_body) {
+    if(is_serialized($rendered_body)) {
+      return $this->decodeEmojisInBody(unserialize($rendered_body));
+    }
+    if(Helpers::isJson($rendered_body)) {
+      return $this->decodeEmojisInBody(json_decode($rendered_body, true));
+    }
+    return $rendered_body;
+  }
+
 }
\ No newline at end of file
diff --git a/tests/unit/Models/ModelValidatorTest.php b/tests/unit/Models/ModelValidatorTest.php
index 949df0e0de..55d1d5948d 100644
--- a/tests/unit/Models/ModelValidatorTest.php
+++ b/tests/unit/Models/ModelValidatorTest.php
@@ -36,5 +36,7 @@ class ModelValidatorTest extends \MailPoetTest {
     expect($this->validator->validateRenderedNewsletterBody(serialize(null)))->true();
     expect($this->validator->validateRenderedNewsletterBody(serialize(array('html' => 'test', 'text' => 'test'))))->true();
     expect($this->validator->validateRenderedNewsletterBody(array('html' => 'test', 'text' => 'test')))->true();
+    expect($this->validator->validateRenderedNewsletterBody(json_encode(null)))->true();
+    expect($this->validator->validateRenderedNewsletterBody(json_encode(array('html' => 'test', 'text' => 'test'))))->true();
   }
 }
\ No newline at end of file
diff --git a/tests/unit/Models/SendingQueueTest.php b/tests/unit/Models/SendingQueueTest.php
index 223b31e09c..de6834a8ee 100644
--- a/tests/unit/Models/SendingQueueTest.php
+++ b/tests/unit/Models/SendingQueueTest.php
@@ -1,12 +1,15 @@
 <?php
+
 namespace MailPoet\Test\Models;
 
 use AspectMock\Test as Mock;
 use MailPoet\Models\SendingQueue;
+use MailPoet\Util\Helpers;
 
 class SendingQueueTest extends \MailPoetTest {
   function _before() {
     $this->queue = SendingQueue::create();
+    $this->queue->newsletter_id = 1;
     $this->queue->save();
 
     $this->rendered_body = array(
@@ -35,8 +38,44 @@ class SendingQueueTest extends \MailPoetTest {
     $mock->verifyInvokedMultipleTimes('decodeEntities', 2);
   }
 
+  function testItReadsSerializedRenderedNewsletterBody() {
+    $queue = $this->queue;
+    $data = array(
+      'html' => 'html',
+      'text' => 'text'
+    );
+    $queue->newsletter_rendered_body = serialize($data);
+    expect($queue->getNewsletterRenderedBody())->equals($data);
+  }
+
+  function testItReadsJsonEncodedRenderedNewsletterBody() {
+    $queue = $this->queue;
+    $data = array(
+      'html' => 'html',
+      'text' => 'text'
+    );
+    $queue->newsletter_rendered_body = json_encode($data);
+    expect($queue->getNewsletterRenderedBody())->equals($data);
+  }
+
+  function testItJsonEncodesRenderedNewsletterBodyWhenSaving() {
+    $queue = SendingQueue::create();
+    $data = array(
+      'html' => 'html',
+      'text' => 'text'
+    );
+    $queue->newsletter_id = 1;
+    $queue->newsletter_rendered_body = $data;
+    $queue->save();
+
+    $queue = SendingQueue::findOne($queue->id);
+
+    expect(Helpers::isJson($queue->newsletter_rendered_body))->true();
+    expect(json_decode($queue->newsletter_rendered_body, true))->equals($data);
+  }
+
   function _after() {
     Mock::clean();
     \ORM::raw_execute('TRUNCATE ' . SendingQueue::$_table);
   }
-}
+}
\ No newline at end of file