diff --git a/includes/common.inc b/includes/common.inc
index a05a09a..1e288e5 100644
--- a/includes/common.inc
+++ b/includes/common.inc
@@ -6426,6 +6426,9 @@ function drupal_common_theme() {
       'render element' => 'elements',
       'template' => 'region',
     ),
+    'datetime' => array(
+      'variables' => array('timestamp' => NULL, 'text_type' => 'medium', 'value_type' => 'datetime', 'text' => NULL, 'attributes' => array()),
+    ),
     'status_messages' => array(
       'variables' => array('display' => NULL),
     ),
diff --git a/includes/theme.inc b/includes/theme.inc
index e50df06..ea57300 100644
--- a/includes/theme.inc
+++ b/includes/theme.inc
@@ -1460,6 +1460,39 @@ function theme_disable($theme_list) {
  */
 
 /**
+ * Returns HTML for a date / time.
+ *
+ * @param $variables
+ *   An associative array containing:
+ *   - timestamp: (optional) The UNIX timestamp for the datetime. If the
+ *     datetime cannot be represented as a UNIX timestamp, instead use a valid
+ *     date string with optional time in $variables['attributes']['value']
+ *     and a human readable string in $variables['text'].
+ *   - text_type: (optional) The format type to use to create a human readable
+ *     string for the text content of the <data> element. This may be a
+ *     built-in date format type ('short', 'medium', or 'long'), a date format
+ *     type defined in hook_date_format_types() if it has a format assigned, or
+ *     the machine name of an administrator-defined date format. Defaults to
+ *     'medium'.
+ *   - value_type: (optional) Either 'date' or 'datetime'. Defaults to
+ *     'datetime'.
+ *   - text: (optional) The text content to display in the <data> element. Use
+ *     this variable if you are providing the formatted date value in
+ *     $variables['attributes']['value'] or if an irregular text content value
+ *     is needed, such as "my birthday".
+ *   - attributes: (optional) Associative array of attributes to be placed in
+ *     the <data> element. If a 'value' attribute is passed in, it will
+ *     override the timestamp. The 'value' attribute must be a valid date
+ *     string with optional time.
+ *     See http://www.whatwg.org/specs/web-apps/current-work/multipage/common-microsyntaxes.html#valid-date-string-with-optional-time
+ *
+ * @see template_preprocess_datetime
+ */
+function theme_datetime($variables) {
+  return '<data' . drupal_attributes($variables['attributes_array']) . '>' . $variables['text'] . '</data>';
+}
+
+/**
  * Returns HTML for status and/or error messages, grouped by type.
  *
  * An invisible heading identifies the messages for assistive technology.
@@ -2582,6 +2615,37 @@ function theme_get_suggestions($args, $base, $delimiter = '__') {
 }
 
 /**
+ * Preprocess variables for theme_datetime().
+ */
+function template_preprocess_datetime(&$variables) {
+  // A 'value' attribute must always be present on the <data> element. If no
+  // 'value' attribute was passed in, format the 'value' attribute from the
+  // timestamp.
+  if (empty($variables['attributes']['value'])) {
+    if (isset($variables['timestamp'])) {
+      if ($variables['value_type'] == 'datetime') {
+        $variables['attributes']['value'] = gmdate('Y-m-d\TH:i:s\Z', $variables['timestamp']);
+      }
+      else {
+        $variables['attributes']['value'] = gmdate('Y-m-d', $variables['timestamp']);
+      }
+    }
+  }
+
+  // If no text for the <data> element was provided, print a human readable
+  // version of the 'value' attribute.
+  if (!isset($variables['text']) && isset($variables['timestamp'])) {
+    $text_type = $variables['text_type'];
+    $variables['text'] = format_date($variables['timestamp'], $text_type);
+  }
+
+  // Preprocess functions usually store attributes in 'attributes_array'. Move
+  // 'attributes' to 'attributes_array'.
+  $variables['attributes_array'] = $variables['attributes'];
+  unset($variables['attributes']);
+}
+
+/**
  * The variables array generated here is a mirror of template_preprocess_page().
  * This preprocessor will run its course when theme_maintenance_page() is
  * invoked.
diff --git a/modules/simpletest/tests/theme.test b/modules/simpletest/tests/theme.test
index fd88124..181ff18 100644
--- a/modules/simpletest/tests/theme.test
+++ b/modules/simpletest/tests/theme.test
@@ -488,3 +488,62 @@ class ThemeHtmlTplPhpAttributesTestCase extends DrupalWebTestCase {
     $this->assertTrue(count($attributes) == 1, t('Attribute set in the body element via hook_preprocess_html() found.'));
   }
 }
+
+/**
+ * Tests for theme_datetime().
+ */
+class ThemeDatetime extends DrupalWebTestCase {
+  public static function getInfo() {
+    return array(
+      'name' => 'Theme Datetime',
+      'description' => 'Test the theme_datetime() function.',
+      'group' => 'Theme',
+    );
+  }
+
+  /**
+   * Test function theme_datetime().
+   */
+  function testThemeDatetime() {
+    // Create timestamp and formatted date for testing.
+    $timestamp = 280281600;
+    $date = format_date($timestamp);
+    $short_date = format_date($timestamp, 'short');
+
+    // Test with timestamp.
+    $variables = array(
+      'timestamp' => $timestamp,
+    );
+    $this->assertEqual('<data value="1978-11-19T00:00:00Z">' . $date . '</data>', theme('datetime', $variables), t('Test theme_datetime with timestamp.'));
+
+    // Test with text and timestamp.
+    $variables = array(
+      'timestamp' => $timestamp,
+      'text' => 'Dries\'s birthday',
+    );
+    $this->assertEqual('<data value="1978-11-19T00:00:00Z">Dries\'s birthday</data>', theme('datetime', $variables), t('Test theme_datetime with text and timestamp.'));
+
+    // Test with text and value attribute.
+    $variables = array(
+      'text' => 'Dries\'s birthday',
+      'attributes' => array(
+        'value' => '1978-11-19',
+      ),
+    );
+    $this->assertEqual('<data value="1978-11-19">Dries\'s birthday</data>', theme('datetime', $variables), t('Test theme_datetime with text and timestamp.'));
+
+    // Test with text formatting.
+    $variables = array(
+      'timestamp' => $timestamp,
+      'text_type' => 'short',
+    );
+    $this->assertEqual('<data value="1978-11-19T00:00:00Z">' . $short_date . '</data>', theme('datetime', $variables), t('Test theme_datetime text formatting.'));
+
+    // Test with value attribute formatting.
+    $variables = array(
+      'timestamp' => $timestamp,
+      'value_type' => 'date',
+    );
+    $this->assertEqual('<data value="1978-11-19">' . $date . '</data>', theme('datetime', $variables), t('Test theme_datetime value attribute formatting.'));
+  }
+}