diff --git a/src/Service/IntrospectionService.php b/src/Service/IntrospectionService.php
index 4677c5f..5da5ed6 100644
--- a/src/Service/IntrospectionService.php
+++ b/src/Service/IntrospectionService.php
@@ -50,10 +50,8 @@ public function introspect(OpenIDClient $client, string $token, array $params =
         $tokenRequest = $this->requestFactory->createRequest('POST', $endpointUri)
             ->withHeader('content-type', 'application/x-www-form-urlencoded');
 
+        $params['token'] = $token;
         $tokenRequest = $authMethod->createRequest($tokenRequest, $client, $params);
-        $tokenRequest->getBody()->write(http_build_query(array_merge($params, [
-            'token' => $token,
-        ])));
 
         $httpClient = $client->getHttpClient() ?? $this->client;
 
diff --git a/src/Service/RevocationService.php b/src/Service/RevocationService.php
index ab2d4ec..52993f0 100644
--- a/src/Service/RevocationService.php
+++ b/src/Service/RevocationService.php
@@ -48,10 +48,8 @@ public function revoke(OpenIDClient $client, string $token, array $params = []):
         $tokenRequest = $this->requestFactory->createRequest('POST', $endpointUri)
             ->withHeader('content-type', 'application/x-www-form-urlencoded');
 
+        $params['token'] = $token;
         $tokenRequest = $authMethod->createRequest($tokenRequest, $client, $params);
-        $tokenRequest->getBody()->write(http_build_query(array_merge($params, [
-            'token' => $token,
-        ])));
 
         $httpClient = $client->getHttpClient() ?? $this->client;