The cast will be made up of:
- Robert Downey, Jr. as Tony Stark / Iron Man;
- Chris Hemsworth as Thor;
- Mark Ruffalo as Dr. Bruce Banner / The Hulk;
- Chris Evans as Steve Rogers / Captain America;
- Scarlett Johansson as Natasha Romanoff / Black Widow;
- Jeremy Renner as Clint Barton / Hawkeye;
- Don Cheadle as Col. James "Rhodey" Rhodes;
- Aaron Taylor-Johnson as Pietro Maximoff / Quicksilver;
- Elizabeth Olsen as Wanda Maximoff / Scarlet Witch;
- Paul Bettany as J.A.R.V.I.S. and Vision;
- Cobie Smulders as Maria Hill;
- James Spader as Ultron;
- Samuel L. Jackson as Nick Fury.
Among others, Hayley Atwell, Idris Elba, Tom Hiddleston, and Thomas Kretschmann reprise their roles from previous MCU films as Peggy Carter, Heimdall, Loki, and Baron Wolfgang von Strucker, respectively. Also, Stan Lee will make a cameo appearance.