Gallagher, who is on loan at Crystal Palace from Chelsea this season, has impressed for Patrick Vieira’s men, scoring four goals and providing two assists in 10 Premier League games for the Eagles.
The 21-year-old’s call up has become necessary following the withdrawals of Jordan Henderson, Jack Grealish and Raheem Sterling from the England squad. Mason Mount, Luke Shaw and Marcus Rashford were not able to join up for the November internationals due to various fitness issues.
The England camp has confirmed Gallagher's arrival in an official statement, which reads: "Conor Gallagher has received his first senior call up to the England senior men’s squad.
"The Crystal Palace loanee will train with the group at Tottenham Hotspur’s Training Ground before travelling with the squad for Monday’s FIFA World Cup qualifier in San Marino."
"Henderson and Grealish have returned to their respective clubs for further assessment on injuries.
"Sterling will miss out owing to a personal matter while Mount (dental surgery) and Shaw (concussion) will no longer link up with the squad."
England need just a point against San Marino to confirm their place at the FIFA World Cup in Qatar next year.