The new 60-seat café will have a monocoque steel shell - prefabricated off site - and a glass front giving visitors spectacular views out across the English Channel.
Commissioned for the client Jane Wood, the single-storey building will replace an existing kiosk and shelter and has been designed to reflect the 'rippling form' of the 'contours etched into driftwood swept up onto the beach'.
Engineer Adams Kara Taylor has also worked on the scheme, which will feature a curved plywood interior created by local boatbuilding specialists.
Heatherwick, who is best known for his sculptures including the 'B of the Bang' in Manchester, explained his design.
He said: 'The seaside at Littlehampton has a raw beauty. It isn't fiddly or fuzzy, or about dolphins and anchors, and our building has been designed to fit into this context.'
He added: 'Our challenge is to build a functional and durable structure on a tight budget, where you can eat Mr Whippy or drink Dom Perignon.'