Edgar Wright is directing the movie, which will hit theaters July 31, 2015.

Marvel has officially confirmed that Paul Rudd will star in Ant-Man.

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Rudd has closed his deal to play the part of the title character, one of Marvel’s first heroes, the company said Thursday night.
Marvel stressed that Rudd was always the company’s first choice, “continuing the studio’s desire to cast actors that bring several dimensions to its onscreen heroes,” according to the announcement.

Rudd’s signing signals that the Edgar Wright-directed movie will have a decidedly comedic bent  -- Chris Evan's Captain America is more earnest and his movies are pure action thrillers, while Chris Hemsworth’s Thor strikes a more aloof tone in its fantasy settings --  and the company is hoping to strike alchemic gold a la Robert Downey Jr. by having someone who is able to straddle comedy and drama.
“When Edgar Wright came to us with the idea of Paul Rudd, we felt a huge sense of relief because the first step in creating any Marvel Studios film is finding the right star," said Marvel's Kevin Feige in  a statement released on Marvel.com. "We knew early on that we had found the right person in Paul. When he not only agreed to do it but became as enthusiastic as any actor we’d ever met with about doing the work, we knew we’d found the right guy. We couldn’t be more excited for our audiences to see what he’s going to do to bring Ant-Man to life.”