Mark Ruffalo was astonished to learn this fact about his ‘Avengers: Endgame’ co-star Brie Larson

Actor Mark Ruffalo could not contain his reaction when he learned a fact about his “Avengers: Endgame” co-star Brie Larson.

Ruffalo, 51, was on the red carpet Monday night at the premiere of the highly anticipated Marvel film. There he learned that he and Larson appeared in another film together. Ruffalo was told Larson appeared in the 2004 film “13 Going on 30.”

“Which one is she?” Ruffalo’s wife, Sunrise Coigney, asked in surprise.

SCARLETT JOHANSSON SIZZLES IN SILVER AT 'AVENGERS' PREMIERE WITH BOYFRIEND COLIN JOST

An “Entertainment Tonight” reporter handed Ruffalo a picture of Larson in the film.

“She was a mean girl!” Ruffalo said laughing.

“Oh my God! That’s amazing. Wow, I didn’t know that,” he continued.

“How cool! I didn’t know that! Did she talk about that?” Ruffalo asked the “Entertainment Tonight” reporter.

CLICK HERE TO GET THE FOX NEWS APP

“She said that’s how she learned she wanted to be a director one day,” the reporter replied.

“Yeah, that was a lovely, little movie,” Ruffalo said of the film. “I didn’t get to work with her.”

Larson portrayed one of the girls who was part of the clique main character Jenna Rink (portrayed by Jennifer Garner) tried to impress.

“Avengers: Endgame” is slated to hit theaters on Friday.