Max Joseph has revealed that Zac Efron was nearly "trampled by groupies" on the set of 'We Are Your Friends'.
The film's director didn't have the budget to hire extras for the festival scene so they threw a free concert in a parking lot but were faced with a slight problem when Zac's diehard fans turned up.
Max - who is best known for his film 'Catfish' and subsequent MTV show 'Catfish: The TV Show' which explores the truths and lies of online dating - exclusively told BANG Showbiz: "The shoot was so crazy. The final day of the shoot is where we shot the scene where they make out in the music festival and they're in the crowd and what was crazy was that, it was a very low budget movie and we didn't really have enough money to pay all these extras to come and be there as part of the concert so we actually threw a free concert for anyone that was interested.
"We got real DJs to come and play ... We had them all come down to a parking lot in downtown Los Angeles and that's where we were filming the scene and it was a bit crazy because there were lot of fans of them in there and we had to have some security that blocked the groupies from trampling Zac and all of us in the process but a lot of the film was shot that way. So that scene was particularly hairy. And they were making out so I actually had to have some of my friends right behind them just to keep things sane. If you look in that scene, my friends are stood right behind Zac and Emily, blocking fans from getting in."
And Max praised Zac, 29, and his co-star Emily Ratajkowski for being "extremely professional" and acting like "soldiers" throughout the shoot.
Asked what it is like to work the pair, he added: "Both of them are extremely professional. Zac's been on sets since he was an adolescent. He knows exactly what to do, he never gets flustered.
"He's very generous and calm and even the paparazzi don't bug him. He's learned to block them out even when they're taking pictures on set when we're shooting, which can be quite unnerving to an actor. And Emily too, just extremely composed and professional ... They were just soldiers and it was a top shoot ... It was funny, there was constantly paparazzi everywhere we went, no matter where it was, even on the beach. Someone just popped out of the tree. It's amazing how dedicated they are to following Zac around."
You can follow Max Joseph on new social network Vero (get.vero.co/maxjosephxvero) to view his film 'D***s' and to explore a wealth of related content.