Police investigating a serious collision on the A509 are appealing to a driver of a car to contact them.
It is believed the silver 'Mondeo' style car, with foreign number plates was travelling along the road, between Wellingborough and Irchester, at around 5am on Sunday, when the pedestrian was injured.
Officers would like to speak to the driver of this car as a potential witness of what took place.
Officers would also like to speak to anyone who may have seen a young man wearing a white shirt and dark coloured trousers, walking from Wellingborough towards Irchester between 4am and 5am on Sunday.
The man who was injured in the collision remains in hospital with serious injuries.
Anyone with information or who witnessed this incident is asked to call the Drivewatch Hotline on 0800 174615.