It may have been just a slip of the tongue, but Anthony Mackie, who plays Sam "The Falcon" Wilson in the Marvel Cinematic Universe, may have accidentally revealed a secret appearance in Captain America: Civil War. During an interview with Radio 1's Movies With Ali Plumb, Mackie listed off his reasons for being excited about Civil War, and why he thinks it's the best Marvel Studios movie yet.
"It's Marvel's best movie so far... It's really, really good. It's because it's more of an acting movie than an action movie," Mackie said (around the 17:30 mark). "I feel like the story is very concise and interesting, and you get to see Robert Downey Jr and Chris Evans and Scarlett Johannson and Mark Ruffalo and everybody just do really, really good acting. And then there's action in it. I think it might be the first superhero movie that might be up for Best Picture."
Bold prediction about the Oscars aside, Mackie specifically mentioned Ruffalo, who plays Bruce Banner and The Hulk in the MCU, alongside people like Evans (Captain America) and Downey, Jr. (Iron Man). In the past, The Hulk's presence in the film has been pretty much completely denied, but this could change that.
Of course, as noted above, this could also just be a slip of the tongue. If you listen to his response, he actually pauses for a moment while doing his list of actors, as if searching for a name, then kind of goes quickly past Ruffalo - it could be he was searching for another name like Sebastian Stan, and said the first thing that was coming to mind.
We'll find out for sure when Captain America: Civil War hits theaters on May 6, 2016.