The stunt actor who stands in for Daniel Radcliffe in the Harry Potter films has been badly hurt on set.
It's been reported in the Mirror newspaper that the 25-year-old stunt actor was working at Leavesden Studios when the incident happened.
It's thought he was filming a scene when a planned explosion went off and he fell to the ground.
Paramedics were called to the set of the film and the stunt actor was taken to Watford General hospital.
A spokesperson for Warner Brothers - who make the Harry Potter films - told the Mirror: "We can confirm a member of the Harry Potter production was injured in an accident.
"We are awaiting further news. Out of respect for the family we are unable to comment further."