Vaughn recently disclosed that he had talks with MGM about reuniting with his Layer Cake star Daniel Craig for the re-launch of the Bond franchise.
"I had a lot of meetings on Casino Royale," he told Empire.
The filmmaker added: "So much so that the head of MGM offered me it. I had a 24-hour period where I thought I was directing Casino Royale."
Vaughn added that it was "a bit of a downer" that the deal was never finalised, with Casino Royale's directing duties instead going to Martin Campbell.
The director is now tackling the spy genre with Kingsman: The Secret Service, starring Colin Firth as a veteran secret agent introducing a young counterpart to the world of espionage.
Vaughn said of casting Firth as a spy: "I just wanted someone where, when he starts kicking the s**t out of people, you cannot believe it's him."
Kingsman: The Secret Service opens on October 17 in the UK and on October 24 in the US. Watch a trailer below: