THIS is the shocking moment a reveller climbed on top of a massive speaker tower at Reading Festival and performed dangerous stunts for fellow festival goers, sparking fears for his safety.

The person, understood to be a teenage boy, climbed to the top of the enormous structure during Eminem's live performance at tonight's event.

Security staff were drafted to the scene and positioned themselves at the bottom of the structure, thought to be around 10m high.

The male could be seen dangling his legs from the top of the tower before performing pull-ups and other stunts as hundreds of people watch on.

Firefighters were called to the festival and arrived shortly after midnight. Crews helped the male down from the tower.

An eye-witness said: "A boy climbed up to the top of the speaker tower and sat there dangling his legs.

"He was playing with his phone and then he started doing pull-ups.

"It's was very dangerous. If he had fallen it must be at least 10-metres high.

"The security staff are down at the bottom of the tower."