diff --git a/lib/oauthlib.php b/lib/oauthlib.php
index bc198b936bf..7f5ea64fe08 100644
--- a/lib/oauthlib.php
+++ b/lib/oauthlib.php
@@ -286,7 +286,11 @@ class oauth_helper {
         }
         // to access protected resource, sign_secret will alwasy be consumer_secret+token_secret
         $this->sign_secret = $this->consumer_secret.'&'.$secret;
-        $oauth_params = $this->prepare_oauth_parameters($url, array('oauth_token'=>$token), $method);
+        if (strtolower($method) === 'post' && !empty($params)) {
+            $oauth_params = $this->prepare_oauth_parameters($url, array('oauth_token'=>$token) + $params, $method);
+        } else {
+            $oauth_params = $this->prepare_oauth_parameters($url, array('oauth_token'=>$token), $method);
+        }
         $this->setup_oauth_http_header($oauth_params);
         $content = call_user_func_array(array($this->http, strtolower($method)), array($url, $params, $this->http_options));
         // reset http header and options to prepare for the next request