The man’s next of kin have been informed.
The lorry stopped at the scene and the driver has not been arrested, police said.
A spokesperson for the London Ambulance Service said: “We were called at 12.57pm this afternoon (July 6) to reports of a road traffic collision in Court Road, Orpington.
“We sent two ambulance crews, a medic in a fast response car and an incident response officer to the scene. The first ambulance arrived in three minutes.
“Sadly, the elderly patient died at the scene.”