The Kick-Ass writer did not confirm rumours that his frequent collaborator had been tapped by Disney for the role, but said that he would be an excellent choice.
It had been rumoured that Vaughn's departure from X-Men: Days of Future Past was connected to the announcement of the new Star Wars film, but Millar recently revealed that the move was made to fasttrack their Secret Service adaptation.
"Vaughn departed X-Men because our Secret Service project was being copied by a few scripts doing the round and we didn't want anyone to beat us out there with our own idea," he wrote on the Millarworld forum.
"Star Wars has since, of course, announced an Episode 7 and he's been touted as a possible director for that movie. All I can say is that if he does get picked to helm the next Star Wars there would be nobody with more passion or enthusiasm for the project.
"I really don't think there could be a better choice, especially as we've referenced Star Wars pretty much every day in the five years we've known one another."
Vaughn directed the 2010 adaptation of Millar's comic book Kick-Ass.
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