Avengers: Endgame stars Mark Ruffalo and Brie Larson both starred in 2004's 13 Going on 30. However, Ruffalo had no idea that Captain Marvel was in the movie until someone pointed it out to him at the world premiere of Endgame earlier this week. The Hulk/Bruce Banner actor knows a lot of things, but most of them are usually spoilers for the Marvel Cinematic Universe, which is why the Russo Brothers gave him a "dummy" script full of fake scenes in their latest movie.

Mark Ruffalo and his wife were both shocked after being shown a picture of a young Brie Larson in 13 Going on 30. Larson was only 14-years old at the time and played one of the mean girls at the beginning of the movie, which starred Jennifer Garner. Video of Ruffalo seeing the photo is pretty hilarious. He had this to say.

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"She was a mean girl. Oh my god, that's amazing! Wow, I didn't know that. It looks like her a lot. It's her."

While Mark Ruffalo didn't know about his Avengers: Endgame costar being in 13 Going on 30, he did admit they didn't shoot any scenes together. He says, "How cool, I didn't know that. Did she talk about that? What did she say? We didn't work together." Brie Larson did know that Ruffalo was in the movie, but as was previously stated, they didn't shoot together and therefore, did not meet at the time. However, it makes for a pretty funny story and one can imagine the two actors discussed it after the Endgame premiere.

As for Brie Larson's experience on the 13 Going on 30 set, the actress says it's what inspired her to be a director. She looked around and saw all of the cameras and immediately wanted to know how everything worked, though she could already envision in her head how everything was going to be edited together. But things didn't exactly go as she planned. She explains.

"I remember it was the moment when I realized that I really wanted to direct. I remember paying a lot of attention to where the camera was and the camera moves, thinking about how I would have cut it together and then seeing the movie and seeing how it differed from what I thought."

Brie Larson's feature-length directorial debut, Unicorn Store, is currently streaming on Netflix. As for the project that brought Larson and Mark Ruffalo back together, it's now open in theaters for the Thursday night preview screenings. Avengers: Endgame is arguably the most-looked forward to movie of the year and the hype surrounding the project has been off of the charts. Hopefully it lives up to all of the expectations surrounding it. You can check out the interview with Mark Ruffalo and Brie Larson below, thanks to the Entertainment Tonight YouTube channel.