Speaking to BBC Sport, Walker heaped praise on the England boss stating "I fully believe in the players that we have in the squad. The manager has brought some brilliant ideas and we've all bought into it.
"I've seen players come and go and it was a different atmosphere before. Now that we all click, I feel quite comfortable sitting with anyone and talking to them, whether it's football or absolutely anything.
"That's the environment that we need to take into the World Cup because the quality in the team is going to show for itself but also the togetherness is going to pull us through."
Walker's fellow teammate for club and country, Raheem Sterling, has also spoken positively about a change in squad morale since his first World Cup in 2014.
"Everyone here gets along no matter what club you're from. Once we get here we're always together, always having a laugh and a joke, so it's great to see."
Both Sterling and Walker took part in a Media Day at St. Georges Park where the national press got a chance to speak to all 23 of Gareth Southgate's players before the tournament.
The England players will now prepare for their last warm up game on Thursday against Costa Rica at Elland Road. All attentions will then turn to the Three Lions' first group game against Tunisia in Volgograd on the 18th June.