Both Dier and Alli are expected to play a key role in Gareth Southgate's team for the tournament, with England having developed a 3-5-2 formation in which Dier or Liverpool's Jordan Henderson is expected to operate as the deepest-lying midfielder.
Alli will also face competition for a starting role from Manchester United's Jesse Lingard, and Dier is confident that both players will be more than capable of handling their defending duties in addition to their attacking ones.
"The pivot entails, in possession, being part of the build-up play as we want to play out from the back. Playing in the pivot, you are the person who most of the time will try to give solutions to all of the back three, try to give angles of support in build-up to try and play out. You try to be the balancer. You have to try to balance out the team - wherever there might be an imbalance, you have to see it and correct it," Dier told the Evening Standard.
"Out of possession, you have to protect the three behind you, work as a three in midfield to try and stop balls in between the lines. That position is as important for organising people in front of you as it is for what you are doing yourself. The part of Dele's game that gets the least attention is his defending, probably because of all the other great stuff he does.
"Dele is actually fantastic defensively, he is very intelligent and reads the game very well. He reacts to the loss of possession very quickly and I haven't played much with Jesse but I feel like he does the same. I don't feel like I am isolated in terms of that. Obviously, I am the most defensive and defensive-minded of the three and I am going to be doing more of that work than them but I believe that it is about how the team functions as a whole. I'm not going to defend by myself and they are not going to attack by themselves.
"It is a formation that is very popular. We've seen it a lot more in the Premier League in recent times and a lot of us play it at our club. For us to come from club football to international football and play in a very similar formation - maybe the style's not the same but the basis of it is - and it makes it easier for us as well."
England's World Cup campaign gets underway against Tunisia in Volgograd on June 18.