Two pedestrians, a man and a woman, were involved in the accident on Mersley Down Road, Isle of Wight, close to the Bestival event site shortly after midnight yesterday.
The accident happened shortly after the evening's headliners The Flaming Lips had finished their set.
The two received medical attention at the scene and were taken to St Mary's Hospital in Newport where the man was later pronounced dead, according to police. A 33-year-old man from Worthing, West Sussex, has been arrested on suspicion of causing death by dangerous driving.
Police are working with organisers of the three-day festival to establish whether any of the people involved in the collision were connected to the event.