The 22-year-old wasn’t expecting to be in the squad after starting just six of Chelsea’s 20 games this season with the club now in eighth place in the Premier League.
Gallagher was honest about his relief to receive the call when sat in the FA’s training base in the suburb of Al Wakrah.
“To be honest, I didn’t expect it,” Gallagher told reporters in Qatar. “I don’t know about percentages, I’m not great at maths. I didn’t really expect it.
“Obviously I was hoping there was a chance. I kept hoping, and when I got the text, I was so proud and honoured. I told my dad first like always.
“He’d always be the first person I’d tell that amazing news to, he’s my biggest fan and my biggest inspiration.
Southgate said he selected Gallagher for his style of play, attitude and his form on loan at Crystal Palace when he announced the squad last week.
There was little mention of his mixed return to Chelsea and Gallagher admits it was a gamble to not return to Palace on loan to secure his spot on the plane.
“A lot of people said I was at a team where I played week in, week out and I would have had more of a chance. [They also said] maybe I haven’t played as much football as I’d like but I am at Chelsea which is my dream club, the team I always wanted to play for.
“I am trying to prove myself there and impress the manager as much as I can. Luckily enough, I was called up for the World Cup is a great feeling. All focus now is on here and training as hard as we can to get ready for the games.”
Former manager Thomas Tuchel was long targeting the return of Gallagher who he believed had many of the same attributes as N’Golo Kante.
It’s a comparison that Gallagher likes but believes is too flattering: “When he said it, it did make me laugh and surprise me a little bit.
“It’s obviously a massive compliment, even if I’m half the player Kante is because I feel like he’s the best midfielder in the world, probably still now when he’s fit.
“We are obviously different players. He probably gets around a bit more than me, he’s a bit sharper than me. So yeah, we’re different players.”
It’s those Kante-like attributes, though, helped Gallagher earn his call with the best running power of all England’s midfielders.
“I feel like I can bring energy going forward and defensively as well,” he added. “In whatever position the manager players me, I will do my best to play it right and be as effective as I can on the pitch. Whether that’s to score goals or try to win the ball back then that’s what I can do.”
Now in Qatar, Gallagher has urged his Chelsea teammates to switch off and regroup.
He expects an improvement upon his return to his club in late December and urged fans to be patient in the rebuild under Graham Potter.
“Yes, it definitely did come at a good time,” he said about going away with his country. “I think we needed it. We needed everyone to get away and regroup in their minds, mainly mentally and come back fresh and raring to go.
“It’s like I said, it is never just an uphill road. With the other teams that started their journey, for example [Mikel] Arteta at Arsenal and [Jurgen] Klopp at Liverpool, they weren’t the best team straight away.
“They start that journey and that’s what Graham Potter is on with us as well. Like I said, I feel we will definitely improve because of the people around the club, the players and staff, and how badly we want to do well for the fans.”