diff --git a/jwt.js b/jwt.js
index <HASH>..<HASH> 100644
--- a/jwt.js
+++ b/jwt.js
@@ -21,6 +21,7 @@ function fastifyJwt (fastify, options, next) {
   }
 
   var secret = options.secret
+  var defaultOptions = options.options
   var secretCallback = secret
   if (typeof secretCallback !== 'function') { secretCallback = wrapStaticSecretInCallback(secretCallback) }
 
@@ -40,6 +41,8 @@ function fastifyJwt (fastify, options, next) {
   function sign (payload, options, callback) {
     assert(payload, 'missing payload')
     options = options || {}
+    options = Object.assign(defaultOptions, options)
+
     if (typeof options === 'function') {
       callback = options
       options = {}
Fix for not able to pass in default options on plugin register.

Example with adding options to be passed in on registration which can be overridden on runtime.
  fastify.register(require('fastify-jwt'), {
    secret: `${fastify.config.jwt.secret}`,
    options: {
      issuer: 'Some issuer',
      subject: 'Some subject',
      audience: 'Some audience'
    }
  })