Schmidt led the Irish into the previous two World Cups, both of which ended with disappointing last-eight exits, before joining the All Blacks’ coaching team last summer.
The 58-year-old’s largely positive six-year tenure culminated in a 46-14 hammering at the hands of the Kiwis at the 2019 tournament in Japan before he was succeeded by his assistant Andy Farrell.
Schmidt is now plotting the downfall of his former employers after switching sides, with Ireland seeking to make history in Paris by stretching their winning run to 18 matches to reach a maiden semi-final.
New Zealand boss Ian Foster publicly outlined plans to tap into Schmidt’s extensive knowledge of the opposition, but Munster wing Earls dismissed the merits of doing so.
“I don’t think Joe would know anything about this squad,” said the 36-year-old. “We’re a completely different squad.
“He probably knows things about individuals but, again, we’ve all changed our habits under this coaching staff and we genuinely don’t use any of the habits that Joe taught us.
“Look, he might have a thing on a couple of individuals, but we’re certainly not the same team that played under Joe.”
Schmidt was due to join the set-up of his native New Zealand following last summer’s three-match home series against Ireland, but he was rushed in early after Covid-19 sidelined Foster and some of his staff.
The All Blacks won the first Test but lost the next two as Ireland launched their current winning streak with a historic tour triumph.
Veteran Earls believes that landmark achievement gave Ireland greater belief, which was enhanced further by this year’s Six Nations Grand Slam success.
Yet he concedes they would be foolish to underestimate the three-time world champions, who have scored 240 points and 36 tries across thrashings of Namibia, Italy and Uruguay following an opening-night defeat to hosts France.
“This tournament is a different animal,” said Earls.
“I know we have beaten New Zealand a few times in the last few years, but they have obviously taught us one or two lessons in between that and beaten us by more than one score.
“We’re under no illusion as to what is coming at the weekend.
“People speak about New Zealand the last year or two that they’ve dipped in performances, but what we’ve seen in this World Cup, they’re starting to come back with a roar.
“After the French game it’s obviously ignited some spark in them. They’re starting to hit their stride again.
“We’re certainly not undermining New Zealand, you would be very silly to do that.
“I have no doubt they will be highly emotional and looking for revenge and bring everything they have.”
Earls hopes to be available to add to his 101 caps after sitting out last weekend’s victory over Scotland due to a hamstring niggle.
He also missed Ireland’s landmark first win over the All Blacks in 2016 in Chicago through suspension, a result, masterminded by Schmidt, which he credits for helping to improve Ireland’s self-image.
“As Irish people, we can lack a lot of confidence and be a small bit too humble at times,” he said.
“We’ve done an awful lot of work on ourselves to believe that we can play a certain brand of rugby that can make us compete with anyone in the world.”