Ant-Man Adam McKay
Adam McKay with Ant-Man on the Comic Con poster revealed earlier this year Getty / Marvel

"We just shaped the whole thing, we just tried to streamline it, make it cleaner, make it a little bigger, a little more aggressive, make it funnier in places."

That's what we should expect from next summer's superhero debutant Ant-Man, according to Adam McKay, the man hired to rewrite Edgar Wright's script.

The Anchorman writer-director was hired in the summer to give the script a final retuning following Wright's 11th-hour departure from the film as director.

In an interview with Collider, McKay – who is leaving directing duties to Peyton Reed – revealed he was anxious about rewriting the script because Wright is a friend of his but said he did so because he believed he would do a good job.

He said: "I was like, 'God this is pretty cool'. Ultimately I didn't want to jump in as a director, I had too many other projects going and it was too tight, but I thought: 'You know what, I can rewrite this, and I can do a lot of good by rewriting it.'"

McKay was not alone in rewriting the script original co-written by Joe Cornish. He was helped out by the film's star, Paul Rudd – who plays Scott Lang, one of the film's two Ant-Men.

"I've always known Paul Rudd's a really good writer from improvising with him on set but I had no idea he was that good – he's really great with dialogue.

"So the two of us holed up in hotel rooms on the east and west coast, and I think it was like six to eight weeks we just ground it out and did a giant rewrite of the script. I was really proud of what we did, I really thought we put some amazing stuff in there and built on an already strong script from Edgar Wright and sort of just enhanced some stuff."

Rudd will play a young man who meets original Ant-Man Hank Pym, played by Michael Douglas. Confirmed story details are thin on the ground but it is believed the film will involve a heist of some kind, making use of Ant-Man's abilities to shrink his size.

"We added some new action beats," McKay said of the rewrite. "I grew up on Marvel Comics so the geek in me was in heaven that I got to add a giant action sequence to the movie; I was so excited. So we did, we added some cool new action. There's a lot that's already in there from what Edgar did, there's a lot of dialogue and character still in there."

Ant-Man also stars Evangeline Lilly, Judy Greer, Michael Peña and Corey Stoll, and will be released on 17 July 2015.