And, quite frankly, it sounds incredible.
"Vaughn is going for a big sci-fi style thing with X-Men: Days of Future Past," Millar said.
"It's X-Men meets The Terminator," he continued.
"You've got robots, you've got time travel, you've got superheroes - it's got everything in one film."
Which sounds to us like the iconic giant robot Sentinels will definitely be appearing in the movie.
Which almost certainly means a bigger budget will be needed. Thankfully, Millar thinks that won't be a problem.
"Cost-wise it's going to go up, and ambitious-wise it's gone up," Millar said. "But Vaughn can handle it. Vaughn made Kick-Ass for $28 million."
X-Men: Days of Future Past should hit cinemas in the UK on 14 July 2014.