Police said the man was believed to be driving a brown Peugeot car which crashed into the central reservation of the M27 between junction 8 and 9, by Park Gate, at about 7.30pm.
The driver then left his car and walked across the westbound carriageway, where he was hit by a Royal Mail lorry.
The 41-year-old was pronounced dead at the scene.
Part of the M27 was shut for about nine hours, until 4.30am, while police began an investigation into the fatal incident.
The route has now been fully reopened.
This morning a Hampshire Constabulary spokesperson said the man’s next of kin had been informed and were being supported by specialist officers.
The lorry driver was uninjured.
The spokesperson added: ‘We are keen to speak to any motorists who were driving along this stretch of the M27 at around the time of the incidents and may have seen anything or has dash cam footage.’
Anyone with information about this incident is asked to call police on 101, quoting reference number 44200499198.