13 Best Secret Cameos In Marvel Movies

4. Nathan Fillion - Guardians Of The Galaxy

Nathan Fillion is one of those actors who has been linked with a role in the MCU almost since the first releases, with Nova often thrown around as his ideal role. But his long-awaited debut in the MCU ended up being a lot more obscure, with Fillion only offering his voice to James Gunn for the first Guardians Of The Galaxy.

He very briefly voiced the CGI alien prisoner who messes with Star-Lord in the Kyln prison and is "made an example of" by Rocket and Groot. He's on-screen for a grand total of about 12 seconds.

He was also due to return for a second cameo in Vol 2 as actor/superhero Simon Williams but his part ended up being cut.