Vin Diesel was shocked after witnessing his stunt double's 9 metre fall on set.

A Hollywood stunt double is in intensive care after plunging 9.1 metres on set in front of the film’s horrified star, Vin Diesel.

Joe Watts, 31, was filming Fast & Furious 9 when a cable he was attached to allegedly snapped at Warner Bros Studios in Hertfordshire. His fiancee Tilly Powell, 27, said her "heart was shattered" after revealing he had been placed in an induced coma with a "serious head injury".

Diesel was said to be in shock after watching his stunt double fall.

Mr Watts and Miss Powell, who live in Surrey, are said to have been together for four years and were set to get married next year.

A source told The Sun: "Vin Diesel was seen on set seconds after (the accident). He looked ashen, totally in shock and blinking back tears. He saw what happened." In 2013, Fast & Furious star Paul Walker, 40, was killed in a car crash off-set.

Hertfordshire Police said: "The incident has been referred to the Health and Safety Executive and there will be no further police involvement."

A spokesman for Universal, the studio behind the film franchise, said: "We had an injury on the set of Fast 9 today. We have halted production for the day to focus on this situation."

Daily Mail