And Southgate's chosen 23 have been reacting to the news on social media, with Kyle Walker, Marcus Rashford and the uncapped Trent Alexander-Arnold among those taking to Twitter.
Arsenal playmaker Wilshere largely put persistent injury woes behind him this season to make 38 club appearances in all competitions.
"I believe this is a squad which we can be excited about", he said.
"The selection process has been over months really, it's not just been the last few weeks. But it doesn't mean anything, really, because we have to keep improving as a team", Southgate told ESPN when asked what he would see as a successful World Cup. "We felt the players all needed to be in on merit after their performances this season".
There was no place for Liverpool's Adam Lallana, though he is one of the players on standby, along with goalkeeper Tom Heaton and defender James Tarkowski from Burnley, Bournemouth's 21-year-old midfielder Lewis Cook and West Bromwich Albion's Jake Livermore.
Wilshere last played for England in one of the country's most humiliating matches, the 2-1 loss to Iceland in the last 16 of Euro 2016, and has had another injury-filled season at Arsenal.
Stoke's Jack Butland is likely to be his deputy, despite conceding the joint-most goals by a goalkeeper in the Premier League this season, with Burnley's Nick Pope providing further back-up.
Southgate's number one goalkeeping choice for Russian Federation is sure to be broached on Thursday morning, along with questions on the captaincy and composition of his stand-by list.
Football.London's Tashan Deniran-Alleyne reports on Gary Cahill's inclusion: "Despite not performing at his very best over the course of the season, it would appear that his experience at major worldwide tournaments has worked in his favour as he's one of four central defenders in the squad alongside John Stones, Phil Jones and Harry Maguire". World Champions-1966 1990-beyond the quarterfinals at broke.
The usual suspects were included in attack and between the sticks, but Burnley goalkeeper Nick Pope's score of 71.3, nearly 12 points better than the perceived number one Jordan Pickford (59.7), certainly provides food for thought.
England is in Group G with Belgium, Panama and Tunisia. "They recognise there's still an opportunity and we've had a lot of conversations over a period of time with them about their situation".