File photo: Paris Hilton [gb.cri.cn]

A drug charge against American socialite Paris Hilton has been droped after she was arrested at a World Cup game Friday, according to media reports.

Ms Hilton and her friend were taken into custody at the Nelson Mandela Bay stadium on charges of marijuana possession after the Netherlands' defeat of Brazil in the quarter-finals of the tournament.

The single count against the heiress was dropped after her friend pleaded guilty to the same charge, police said.

Ms Hilton's spokeswoman said "I can confirm that the incident was a complete misunderstanding and it was actually another person in the group who did it. The case has been dropped against Paris and no charges will be made."

Hilton appeared calm when she showed up before a magistrate judge in Port Elizabeth, media reported.