A high school musical in New Zealand got a little too real this week when a prop razor used in a throat-slitting scene ended up cutting the necks of two boys and sending them to a local hospital overnight.

Students at Saint Kentigern College in Auckland were performing the opening night of Sweeney Todd before parents and other audience members Wednesday when things went badly wrong. Set in Victorian London, the musical depicts a barber who slits his customer's throats with a razor and uses the bodies to make meat pies.

The head of Saint Kentigern College, Steve Cole, told radio station Newstalk ZB the razor used in the show was real but had been bound in duct tape. He said he has no idea what went wrong during a scene midway through the Second Act.

"It had been bound in Cellophane, bound in all sorts of things," he said. "It was very non-sharp, blunted, and had been through all sorts of health and safety checks. It was a very unfortunate mishap."

He said the boys were released from hospital Thursday and were doing well.

"We've been keeping contact through the family and making sure the kids are OK," he told the radio station.

Cole said a performance of the play scheduled for Thursday was canceled but he hoped the show could resume Friday.

"Obviously without those particular props," he added.

Police and health-and-safety officials are investigating the incident.