The panel began with the showing of a teaser trailer first look at Chris Evans in his role as Captain America before also showing Hugo Weaving in character before his transformation into supervillain the Red Skull.
Marvel Studios then brought out cast members from 2011's Thor including Chris Hemsworth, Natalie Portman and Tom Hiddleston.
CBR reports Hiddleton teased that his interpretation of Loki would be as: "The agent of chaos and also the damaged younger brother."
Samuel L Jackson then arrived on stage to introduce the full cast of The Avengers including the previously announced Scarett Johansson, Chris Hemsworth, Chris Evans and Robert Downey Jr.
It was confirmed that Jeremy Renner would play Hawkeye, Mark Ruffalo would be the new Bruce Banner and that Joss Whedon will direct the film.
"I've had a dream all my life, and it was not this good," Whedon told the audience. "This cast is more than I could ever dream of working with, and I am going to blow it."
It was previously rumoured that Whedon favourite Nathan Fillion and Desperate Housewives star Eva Longoria would be announced as superheros Ant-Man and The Wasp respectively, but neither character was mentioned at the panel.