The Hollywood Reporter said Downey signed a four-picture deal with Marvel Studios that retroactively includes the 2008 blockbuster "Iron Man" in addition to two "IM" sequels and "The Avengers."

Jon Favreau, who directed "Iron Man" and is helming its first followup, is to executive produce "The Avengers," the entertainment industry trade newspaper said.

Don Cheadle will replace original "IM" cast member Terrence Howard as Jim Rhodes, Stark's best friend, in "IM2" and "The Avengers."

"The Avengers" sees Iron Man, Captain America, the Hulk, Wasp, Giant Man, Hawkeye and Thor joining forces to fight evil. It is scheduled for theatrical release in 2011.