Ben Chilwell has been called up to the England squad after Luke Shaw was forced to withdraw with injury.
The Leicester City defender made his international debut last month but had returned to the under-21 set-up prior to the news that Shaw, injured in Manchester United's win over Newcastle United, would not be fit to feature in the upcoming UEFA Nations League double-header.
Chilwell has now linked up with the senior England squad again after Shaw returned to United, with fellow left-back Danny Rose also reportedly struggling with a fitness concern.
Southgate took the opportunity to bring in a number of young stars, including Jadon Sancho, Mason Mount and James Maddison.
The Three Lions have already handed Brighton and Hove Albion centre-back Lewis Dunk a first international call-up as well after James Tarkowski suffered an injury setback.