More on KentOnline
Fire crews were called to the esplanade after a fitness group spotted a "little flash" which turned out to be a car ablaze.
Exercisers were doing their stretches along Rochester Esplanade shortly after 8.30am when they spotted a red Corsa alight outside the castle grounds.
Erica Thuell was exercising with the Tough Mumma Bootcamp when she said her instructor saw a "little flash, like glitter" which caught her eye.
"When she looked again a minute later she realised there was smoke coming from the bonnet, " she said.
The class then dispersed into separate groups to stop the traffic.
Leanne Ilsa, also from the mum's group, said she put in a call to the fire brigade who turned up "within minutes".
She said: "I was on the Esplanade, when we noticed the flames from the drivers side.
"There were flames coming from underneath the tyre.
"We managed to stop a few cars and use them to block the road further up to stop traffic driving through."
One fire engine was sent to the scene to tackle the blaze.
No other cars parked nearby were damaged.
She said no one returned to the vehicle while they were there.
Following the blaze a man posted on Facebook to claim the car belonged to him.
He said he did not know what had happened but was unharmed in the incident.
Kent Fire and Rescue service said the cause is not yet known.