A section of the M20 will be closed until at least midday after police found a body on the road.
Officers were called at 6.05pm on Tuesday to the London-bound carriageway between junctions 10 and nine near Ashford.
A body was found on the road and the person was pronounced dead at the scene, Kent Police said.
The death is being treated as unexplained and the force is appealing for anyone who saw a pedestrian in the area to come forward.
Highways England tweeted that the road will likely remain closed for ongoing investigations following a very serious incident, with drivers initially told to remain in their vehicles until police officers directed them to turn around.
The motorway provides a link from the capital to the Channel Tunnel and ports of Dover. P&O Ferries tweeted to warn drivers to use an alternative route.
Anyone with information should call the Kent Police serious collision investigation unit on 01622 798538 quoting 20-0913.