“He gave me a lot of responsibility from the day I walked in the door, to improve the group and try to take the club forward.
“The amount of respect he has from the squad is huge. He’s come into a big club and turned things around.
“Players are loving their football again, but he’s always demanding more and we haven’t achieved anything yet.”
The call from Cooper was impossible for Cook to resist, at a time when he was out of the first-team picture under Bournemouth manager Scott Parker.
With his contract expiring this summer, plus the addition of former England international Gary Cahill in August, Cook knew the writing was on the wall.
It was still an incredibly emotional moment when he said his farewells: he was a former captain and a crucial figure in Bournemouth’s recent history, making nearly 400 appearances, while he was also renowned for his work in the local community.
“It was a huge move and tough to leave but I’ve had to take myself out of my comfort zone,” he says.
“The ten years I had at Bournemouth were incredible, a third of my life playing in leagues I never dreamed I’d play in.
“To experience that success was unbelievable but it was a perfect time to go. I’d gone from playing every week to not even being in the squad.”
Despite all the positivity around his move to Nottingham, Cook admits it has also been a period of adjustment.
“Living away from my family is difficult, it’s that side of football people don’t realize. My kids are in school down south and I can’t take them out. We’ve found a house now and they are all moving up here in the summer.
“I’ve only been here two months but I feel like I’ve been here ten years. I feel like this move is bringing another level to my game.”
Cook has established a fine partnership in Cooper’s preferred back-three, which also includes captain Joe Worrall and Scotland international Scott McKenna.
Since Cook’s arrival, Forest have managed six clean sheets in 11 matches and operate with a formation that encourages defenders to play out from the back.
Much of the attention this season, however, has been on youngsters Brennan Johnson and Djed Spence, who were both hugely influential in the cup successes over Premier League opposition.
Johnson is an attacker who was the subject of an £18 million bid from Brentford in January, while Spence, a wing-back signed on loan from Middlesbrough, is attracting interest from all over Europe.
“They are top players with promising careers ahead of them,” says Cook.
“It’s going to be key how they handle themselves with the added pressure of teams trying to take them out of the game. They are a huge part of this team.
“As one of the more experienced players I speak to them a lot, but they’ve got good people around them.
“Brennan obviously had an opportunity to move on but I know for a fact that he was advised to stay at Forest. They’ve played a lot of games and know what they need to do.”
After Forest’s dramatic finale at Sheffield United on Friday night, securing a draw in injury time, the full focus is now on Huddersfield.
Second in the Championship, and unbeaten in 18 games, Huddersfield will represent a severe threat to Forest’s hopes of hosting Jurgen Klopp later this month.
“It’s potentially more difficult than Arsenal and Leicester because they know our game as they’re in our league,” says Cook.
“Huddersfield play in a very unique way and this is going to be far from easy.
“We want to be where they are in the table, so this is as hard a cup tie as we could possibly face – but these are the stages we want to be on.
“At Bournemouth we were terrible in the FA Cup, apart from last year, so this is a real opportunity to upset the odds.”
George Holan is chief editor at Plainsmen Post and has articles published in many notable publications in the last decade.