Crushed vitamin pills doubled up as cocaine in Vanessa Hudgens and Selena Gomez's provocative new movie Spring Breakers.

The young stars were happy to simulate the drug use for the cameras but they did not expect to experience the surge of energy they did after snorting the powder - and they reveal their behavior had some cast and crewmembers wondering if they really were high on coke.

Hudgens tells Paper magazine, "We would run around set like mad men, and people would wonder, ‘Did you switch that out with anything?’"

The actresses play two of four college girls who are forced to work for a drug and arms dealer when he bails them out of jail after they're accused of robbing a restaurant in order to fund their spring break vacation.