It's no secret that the Avengers: Endgame co-stars have strong work relationships with one another, and let's face it—at this point, it seems like half of Hollywood has been a member of the extended Marvel Cinematic Universe. Just look at the starry cast of the MCU's first big franchise finale, Endgame: at the world premiere in Los Angeles this week, they could hardly all fit on one stage at the film's world premiere.

If you watch any of the press junkets or pay attention to their social media blasts, it is all too obvious that the core Avengers have good chemistry, and maybe that's because most of them have already starred together in other projects, or will co-star alongside one another in a future outside of Marvel.

They say there are six degrees of separation, but for most of the Avengers: Endgame co-stars, there are even fewer. Some have had cameos in each other's films, and others have taken top billing alongside their fellow superheroes. All of the Hollywood Chrises (save Pine, who, while being a member of the DC Comics Universe and the Star Trek franchise, is technically also part of the Marvel universe because he voiced Peter Parker in Spider-Man: Into the Spider-Verse last year) appear in Avengers: Endgame, but they've crossed paths in other films before. Samuel L. Jackson has been working in Hollywood since the early '70s, so you know he's co-starred in a movie or two with at least one of the Avengers, and Scarlett Johansson has made the rounds with a few of her cast-mates in other films as well. Their individual filmographies are a lot to keep track of, but we've mapped out the 11 times you should know that the Avengers co-stars appeared in movies together, before they put on their super suits.

13 Going on 30

Brie Larson at far right.

13 Going on 30

You may have missed this one 15 years ago, but Mark Ruffalo and Brie Larson did star in 13 Going on 30 together, technically. Larson played a six chick from the '80s and Ruffalo played the grown-up version of Matt Flamhaff (the love interest to Jennifer Garner's Jenna Rink), so they never shared a scene until the former grew up and became Captain Marvel.

Don Jon

Scarlett Johansson may have received top billing, right next to Joseph Gordon-Levitt as the titular Don Jon, but Brie Larson made a wry appearance in a few scenes as Jon's sister, Monica Martello, who spends a lot of time on her phone and disapproves of her brother's girlfriend.

Zodiac

Mark Ruffalo plays a private investigator and Robert Downey Jr. plays a reporter, but they both share the same goal: catching the Zodiac serial killer in David Fincher's Zodiac. This movie also gets bonus points for the inclusion of Jake Gyllenhaal, who will soon join the Marvel cinematic universe as Mysterio in Spider-Man: Far From Home.

The Perfect Score

Bryan Greenberg, Scarlett Johansson and Chris Evans in The Perfect Score.

The Perfect Score/Paramount Pictures

When Chris Evans was in his teen rom-com phase, so was Scarlett Johansson, and they both ended up cast together in The Perfect Score, a movie about high school students scheming to fix the SATs so that they could get into the colleges of their dreams.

MIB: International

Sony Pictures

This movie is yet to be released, but Tessa Thompson and Chris Hemsworth will team up to work together to fight aliens outside of the Marvel universe. This time they will play international agents instead of Norse gods Valkyrie and Thor.

Oldboy

Nick Fury, Scarlet Witch, and Thanos all appeared together in Oldboy, which is Spike Lee's remake of Park Chan-wook's 2003 film of the same name.

Hard 8

Back in 1996, Gwyneth Paltrow and Samuel L. Jackson co-starred in Hard 8, a neo-noir mob thriller in which the former plays a casino cocktail waitress named Clementine who marries a gambler; the latter plays a man named Jimmy who tries to put the gambler in his place.

War Horse

DreamWorks Pictures/War Horse

Yes, Loki and Doctor Strange have been in a movie together, as a Captain and a Major in Steven Spielberg's historical drama War Horse.

What's Your Number?

In a tale of two Hollywood Chrises, Pratt plays "Disgusting Donald," an ex-boyfriend of his now real life ex-wife Anna Faris's character, and Evans plays Colin, the current love interest of the character.

The Words

CBS Films/The Words

Once upon a time,, Bradley Cooper and Zoe Saldana starred opposite one another in The Words, a romantic drama about a fictional writer whose work keeps getting rejected. This was long before Guardians of the Galaxy, and way more relatable.

Kong: Skull Island

Kong: Skull Island/Warner Bros.

You know Carol Danvers and Nick Fury already worked in Kong: Skull Island, right? And Loki was there, too.

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