Louis Leterrier has revealed getting Jesse Eisenberg and the rest of the Now You See Me cast together for the sequel has been a "nightmare".
The French filmmaker, who will return to direct the follow-up, admitted the ensemble cast, including Jesse, Mark Ruffalo, Woody Harrelson, Isla Fisher, Sir Michael Caine and Morgan Freeman, have not committed to the sequel yet.
"We are talking to everyone. No one signs onto sequels without approving the script," he said.
Jesse, Woody, Isla and Dave Franco played street magicians who carried out heists, with Mark as the cop on their tail.
The 40-year-old continued: "It's amazing to do a movie with a cast like this - putting it back together is a nightmare. Everyone is extremely busy and one thing an actor doesn't like to do is stay at home, waiting for the phone to ring, so getting all the actors back is a tough one."
Louis, who has been working with writers to get the right script and scouting for locations, promised that the follow-up will be better than the original.
"The first one was mostly in America so we are debating where to shoot the sequel - we want to shoot it somewhere else. I'm coming to London to see if we can do something there, then France and other places," he said.
"Jesse is the one who asks me, 'What's happening? Why is it taking so long?' It's a very tough one to crack because we want to do a sequel that's as good, if not better than the first one."
Louis admitted the film's success was a "surprise", saying: "We were so happy and dumbfounded . It's one of those rare moments where you think, 'This one actually worked'."
Now You See Me is out on DVD and Blu-ray now.