Hathaway, 20, who has represented both Wales and England at Under 20 level, can play at either full-back or on the wing.

He is joined in coach Warren Gatland's squad by three other uncapped players - Ospreys wing Keelan Giles and Cardiff backs Jacob Beetham and Ellis Bevan.

Wales are looking to bounce back from a dismal Six Nations when they lost all five matches to finish bottom for the first time since 2003.

But they are set to be without their England-based players, including Six Nations captain Dafydd Jenkins, the Exeter lock, for the Twickenham encounter against the world champion Springboks on June 22.

Non-Welsh clubs are under no obligation to release players for a match that is being played outside World Rugby's international window.

An updated squad of 34 players, who will travel to Australia for Tests against the Wallabies on July 6 and 13 will be confirmed following the South Africa match.

Wales training squad:

Forwards: Corey Domachowski, Kemsley Mathias, Gareth Thomas, Elliot Dee, Dewi Lake, Evan Lloyd, Sam Parry, Keiron Assiratti, Archie Griffin, Dillon Lewis, Harri O'Connor, Henry Thomas, Ben Carter, Cory Hill, Dafydd Jenkins, Matthew Screech, Christ Tshiunza, Mackenzie Martin, Jac Morgan, Taine Plumtree, Tommy Reffell, Aaron Wainwright

Backs: Ellis Bevan, Gareth Davies, Kieran Hardy, Sam Costelow, Mason Grady, Ben Thomas, Nick Tompkins, Owen Watkin, Rio Dyer, Keelan Giles, Josh Hathaway, Liam Williams, Jacob Beetham, Cameron Winnett