Martin Boyle played with David Gray at Hibs for seven years, but now faces a club fine if he calls him mate.
After four spells as interim manager, Gray is embarking on his first season in permanent charge with Boyle revealing some of the changes at Easter Road.
"I was away with the Socceroos when I first got that call with him when he got the job and I was asking what do I call him. There's a fine system in place if you call him mate not gaffer so I've just adapted to that," the striker told Sky Sports News.
"The boys are fully on board on what he wants to do. He was a leader when he was the captain here and I was obviously a team-mate with him for a long time.
"He's a mate but that goes out the window when he's your manager now and we want to follow the direction he's going and I believe he'll take us there.
"He's been the interim manager a few times and he knows how to flick that switch quickly and he's adapted really well.
"There's no doubt he'll be a successful manager. I never really thought he'd do it that early in his career but fair play to him, it's brilliant and I'm ecstatic to play under him.
"Everyone is chirpier around the place, everyone is buzzing and training's been really good."
Hibs failed to finish in the top-six last season with both Lee Johnson and Nick Montgomery sacked during a disappointing campaign.
Boyle, who was part of Hibs' Scottish Cup winning team with Gray in 2016, is confident there will not be a repeat.
"[We need to] correct some wrongs from last season and finish above where we did last season. For a club of this stature it was unacceptable and the performances were not good enough," he added.
"I feel we need to be a lot more together as a unit and I think Dave has brought that out in us.
"We've made a good few signings, we've lost a few boys but I feel if we've got that togetherness I'm sure we can go far.
"We want to break into that top-six, we want to get Europa League and be competing in the cup competitions."
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