If you think you know every star who's made an appearance in the MCU you're probably wrong. Cameos are the order of the day in Marvel films.

For anyone who has seen Avengers: Endgame the most impressive part of the movie isn't really the special effects or even the acting. It's the way the script was organized to give every single one of the seeming thousands of A-list stars time to shine on-screen.

This balancing act of characters is a miracle to behold and is probably not even recognized by most viewers. But if you thought you knew every star who made an appearance in the MCU, the massive team effort the was The Avengers included, you'd probably be wrong. There are a few very famous faces you might not have noticed appearing in Marvel properties over the years, so here are just a few you should look for.

10 Peter Billingsley - Iron Man

That's right, the tradition of famous cameos began with the Marvel Cinematic Universe itself. In honor of the recent Christmas holiday, the first celebrity sighting we want to point out is Peter Billingsley, better known for his starring role in A Christmas Story as cherubic child Ralphie. Wondering where he appears in the original Marvel movie Iron Man? Billingsley makes his appearance near the giant arc reactor at Stark Industries. He's the poor guy who has to tell Jeff Bridges' Obadiah Stane that they have not been able to shrink the technology as he requested.

9 Lou Ferrigno - The Incredible Hulk

That's right the original television Incredible Hulk does make an appearance in The Incredible Hulk, starring Edward Norton. The original green guy appears as a regular security guard who Norton bribes with pizza in the movie. In other news, Ferrigno was also used behind the scenes to help create some of the noises the big green guy makes once he's ready to smash, rather than sneak around as a scientist. It's like the Marvel Cinematic Universe likes to reference itself over and over and over again, but fans aren't going to complain about these excellent easter eggs.

8 Kate Mara - Iron Man 2

Did you know that the Invisible Woman made an appearance in Iron Man 2 before she was even cast as the Invisible Woman? Kate Mara appears in a single scene, offering Tony and Happy the subpoena summoning Stark to Washington, DC. Who knew she would rise from U.S. Marshall to actual superhero?

Apparently no one (at the time). But it's some interesting trivia to know and share at parties as the MCU becomes more and more entwined.

7 Elon Musk - Iron Man 2

Iron Man 2 came out on the heels of the incredible success of the first Iron Man movie and, apparently, more people wanted to make an appearance (now that success was guaranteed). In Monaco, Tony Stark runs into real-life billionaire Elon Musk, founder and CEO of SpaceX. Tony and Elon have a quick back and forth about the actual engineering projects at Musk's company, including the engine used in SpaceX rockets. One wonders how much faster the United States would be returning to the moon or going off to Mars if Tony Stark, instead of Elon Musk, were the real-life billionaire engineer.

6 Natalie Dormer - Captain America: The First Avenger

Like Kate Mara before her, Natalie Dormer dropped into a Marvel movie right before hitting it big elsewhere in the entertainment industry. Dormer plays a U.S. Army soldier who attempts to seduce a newly powerful Steve Rogers before they are interrupted by Hayley Atwell's Peggy Carter. This all took place before Dormer exploded onto the screen as Margaery Tyrell in Game of Thrones on HBO. While her powers of seduction did transfer to this new fantasy universe, Dormer was given much more agency as Tyrell, and much more screen time as well.

5 Nathan Fillion - Guardians of the Galaxy

Fans of Firefly and Castle will no doubt be pleased to hear that Nathan Fillion, Captain Mal Reynolds himself, spent some extra time in space as a big blue alien. The big deal with this big blue alien? He's the one on the prison ship who gets Groot's tree limb punched up his nose. Like Mal Reynolds, this alien seems to have bitten off a little more than he can chew in this instance. Don't make new enemies if you don't know you can defeat them.

4 Rob Zombie - Guardians of the Galaxy 2

Here's the man this list is named for, though he didn't get his shot until the second Guardians of the Galaxy movie made its debut. Rob Zombie, a founding member of the heavy metal band White Zombie, happens to be friends with Guardians director James Gunn. Gunn didn't make his friend appear onset in any sort of silly alien makeup but rather had him voice the navigation system on the Ravager. Like Jarvis before him, all technology systems that come with voices are very well respected in the Marvel Cinematic Universe.

3 Miley Cyrus - Guardians of the Galaxy 2

Rob Zombie was not the only musician to get a little attention in James Gunn's Guardians of the Galaxy 2. Neither was he the only special celebrity to get to offer his voice as a talent rather than his person. In one post-credit scene to the film, we see the Guardians 3000 team (from the comics) headed by Sylvester Stalone.

Who you probably didn't notice in this little group? One Miley Cyrus, pop star. Miley's voice can be heard as the character Mainframe on board with Sylvester and company.

2 Matt Damon - Thor: Ragnarok

When Thor gets back to Asgard things seem a little bit off. Odin is preoccupied. He's eating grapes and watching a theatrical depiction of recent events starring himself, along with sons Thor and Loki. But what godly thespians have donned the garb of Asgard's royal family? Well, if we look at the actor portraying Loki fans will recognize the very famous Earth actor, Matt Damon. While he does not appear in the credits for his role, Damon is luckily recognizable enough to have been noticed, even in this small part.

1 Kenneth Branagh - Avengers: Infinity War

For most fans of the Marvel Cinematic Universe, Sir Kenneth Branagh is best known as the director of the first Thor film. That, however, is not the only time Branagh participated in the MCU. At the beginning of Avengers: Infinity War a distress call is heard issuing from an Asgardian ship where Thanos has attacked. While fans were obviously distracted and worried about the fates of Thor, Loki, and Heimdall during the movie, it might be interesting to know now that the voice of the distress call was provided by the Thor director and Shakespearean actor himself.

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