Hunger Games: Mockingjay Part I Secrets Revealed: 5 Special Details From the Set

Us Weekly has unearthed five amazing secrets from the set of The Hunger Games: Mockingjay - Part I, including who stole Jennifer Lawrence's wig, which two stars danced to Beyonce's "Single Ladies," and more. Credit: Murray Close

Go big or go home! The producers behind The Hunger Games franchise went all out to set the scene for The Hunger Games: Mockingjay - Parts I and II. Us Weekly has unearthed five amazing secrets from the movie's set, including funny inside stories about stars Jennifer Lawrence, Josh Hutcherson, Liam Hemsworth, and more.

1. It Took Three Cities to Create Panem

13 districts, two continents, three cities, and one Panem. Filming for Mockingjay took place across three different cities including Atlanta, Berlin, and Paris. "We filmed in the French countryside during spring, when the wildflowers were blooming," Jena Malone (Johanna Mason) tells Us. "It was a joy! I'd roll around in the grass and take photos and everyone would be like, 'Where's Jena?'"

Her costar and newcomer Natalie Dormer (Cressida) says the history behind certain locations was what fascinated her most. "It was pretty amazing," the Game of Thrones actress recalls. "We filmed at Hitler's Tempelhof Airport and explored some old Nazi Barracks. And we were in Berlin on the 70th anniversary of D-day. It felt very profound to all of us."

2. Jennifer Lawrence's Katniss Wig Was Stolen!

The natural blonde had to wear a brunette wig in the final two installments of the franchise due to hair damage after dying her tresses for the first two films.

It turned out that one of her castmates was all about Katniss' wig, too. Evan Ross (Messalla) once swiped the star's wig and did what any pal of J.Law's would do: He put it on himself. "I put it on my head and knocked on Jen's trailer," Ross (who recently wed Ashlee Simpson) recalls with a laugh. "She was like, 'What is wrong with you?' It was so funny!"

3. One of the Most Expensive Film Productions of All Time

Part I of Mockingjay alone had a $250 million budget, making it one of the most expensive movie productions of all time. Along with its core cast including Oscar winners Philip Seymour Hoffman and Julianne Moore, the film hired more than 400 extras. The two parts of the final installment in author Suzanne Collins' The Hunger Games franchise were shot together over the course of nine months of filming. "We had to, because these two stories connect seamlessly together," director Francis Lawrence tells Us.

4. Shooting Special Effects Was Not as Exciting

Viewers will have a more thrilling experience in theaters than the actors, who experienced a more tame encounter on set. The most explosive action featured in the adrenaline pumping flick was added later via CGI.

"Basically, we had to react to someone with a megaphone saying 'Boom' in a really bored voice," Willow Shields (Katniss' little sister Prim) tells Us. "I have to admit, on the first take I was kind of laughing!"

5. Boogie Nights and Beyonce!

Let the Games — or more like hijinks begin! "We were laughing 100 percent of the time between takes," Mahershala Ali (Boggs) tells Us. To lighten up the atmosphere, the group would goof around when they weren't filming the pulse-racing, emotionally-draining scenes. Lawrence and Woody Harrelson (Haymitch) would race to the set and Hutcherson and Hemsworth punched each other nonstop. Their friendships extended beyond the set of the movie.

The stars oftentimes met up to explore Paris and Berlin, enjoy home-cooked meals, and enjoy the local club scenes offered in each of the cosmopolitan cities. Sam Claflin (Finnick) and Hutcherson once busted into Beyonce's "Single Ladies" dance, complete with her signature "put a ring on it" moves.

"We're like, 'Wow,'" jokes Lawrence. "We actually buckled down and did a move!"

For more insider details, pictures, and posters from The Hunger Games: Mockingjay - Part I, pick up Us Weekly's special bookazine issue, on stands and at BN.com now!