Jarrad Branthwaite, Ivan Toney, and Joe Gomez are among the surprise inclusions in the Three Lions squad for matches against Brazil and Belgium.
England captain Harry Kane retains his spot and will be joined by Toney and Ollie Watkins as the other recognised strikers in the group.
There's no room for Kalvin Phillips, who misses out on the final international break of the season.
Speaking to the media following his squad announcement, Southgate admitted the midfielder hadn't played to the right level to be included.
"Unfortunately, his form just hasn't been good enough," said the England manager.
"I've spoken to him about that, he understands. He has all the attributes to force his way back in and we're really keen for him to do that."
Branthwaite has enjoyed a stellar campaign at the heart of Everton's defence, while Toney has recently returned to football following an eight-month ban for breaking FA gambling rules.
Gomez returns to the England squad for the first time in nearly four years after an excellent run of form for Liverpool, putting in top performances at left-back, right-back and even midfield.
Anthony Gordon has been handed a call-up, although the Newcastle winger appeared to pick up a serious knee injury in the Magpies' recent defeat against Chelsea.
Blues forward Cole Palmer, as well as West Ham winger Jarrod Bowen, are also in the squad - while long-term servants Harry Maguire, Kyle Walker and Jordan Pickford also keep their spots.
The Three Lions face Brazil on March 23rd before welcoming Belgium three days later on the 26th.
