Ben Spencer is in line to make his Rugby World Cup debut in Saturday's final after the Saracens scrum-half was added to the England squad as an injury replacement for Willi Heinz.
England announced on Sunday morning that Spencer would fly out to Japan to provide emergency cover after Heinz sustained a hamstring injury during the stunning 19-7 semi-final win against New Zealand.
Gloucester half-back Heinz, who came on in the 63rd minute to replace first-choice Ben Youngs, played on until the final whistle of the match at International Stadium Yokohama but the Rugby Football Union have acted quickly to call up cover.
Spencer, who took part in England's pre Rugby World Cup training camps during the summer, has won three international caps as a replacement and will now act as Youngs' deputy against South Africa.
Meanwhile, Heinz will remain with the squad at their training base in Tokyo.