Firefighters were called to Battersea Power Station last night after witnesses believed a stunt for a Bear Grylls TV show had caused the famous landmark to go up in flames.
Flames were projected onto the landmark as Grylls abseiled down to launch his latest show Bear Grylls: Escape From Hell.
Plumes of flame then came up from the ground.
The stunt was so realistic that one worried witness called London Fire Brigade to say the building was ablaze.
A fire brigade spokesman said: "We were called at 7.50pm. We attended and as soon as we got there we realised it wasn't an incident for us."
He added: "We take every call seriously."
Thousands of people queued to take a look inside Battersea Power Station at the weekend.
The Open House project offered the last opportunity for visitors to see the giant Art Deco structure before it undergoes a multimillion-pound redevelopment across the full site.
Bear Grylls: Escape From Hell will be shown on the Discovery Channel.