A costume trailer for Stephen Merchant's TV series The Outlaws has plunged into a city centre harbour.
The lorry fell into the water at Bristol Harbour at 07:19 BST and ended up partially submerged.
No-one was injured but nearby boats have been evacuated and cordons are in place near to the truck.
The lorry is owned by Wandering Star Facilities, who leased it to TV vehicle support group ADF for the production, which was being filmed in the city.
Three fire engines, one heavy rescue tender, a boat and firefighters are using winches in an effort to stop the HGV from sinking.
A production spokesperson for The Outlaws said: "An accident occurred involving one of our production vehicles. No-one was hurt or in the vehicle.
"We are investigating what happened and working on removing the vehicle as quickly and safely as possible."
Phil Worgan, who was staying on a boat nearby, said he heard shouting and a big crash at the time.
"I thought someone was about to jump or was in the water, but when I looked, it was a truck," he said.
Mr Worgan said a number of lorries had been at the site near Millennium Square for a few days.
"Apparently they were trying to hook it up and it just rolled in," he added.
Avon Fire and Rescue Service group manager Gareth Lloyd said the recovery will be a long and technical task.
"On arrival, crews found one HGV submerged in the water, the driver had already made it to safety," he said.
"The lorry is now secure and firefighters remain on scene to assist the recovery company in removing the vehicle."
The harbourmaster and Bristol City Council have been informed of the incident.
It is understood that filming on The Outlaws finished at about 05:00 BST on Thursday morning.
Filming on the TV series started in March 2020, but only got ten days in before it had to close down due to coronavirus restrictions. It restarted in October this year.
The Outlaws starts on BBC One on Monday.