Robert Downey Jr. shares new "Avengers" poster, teases big announcement

Robert Downey Jr. decided to treat Marvel fans to a new "Avengers" poster on Wednesday -- but that's not all Tony Stark/Iron Man's got up his sleeve.

The actor shared an Iron Man poster from the upcoming "Avengers: Age of Ultron" on his Twitter page, adding that he's also got a "big announcement" coming.

What could the announcement be? Downey didn't say -- but did note that fans should "get excited." We don't think that will be hard to accomplish.

"Avengers: Age of Ultron" hits theaters on May 1.