It isn’t often that you hear about the “friendship” between college football player and football coach.

One is instructing, the other is learning and implementing. The very nature of the interaction dictates a hierarchy, a demarcation that keeps the two at arm’s length at the very least.

Notre Dame quarterbacks coach Tom Rees and Notre Dame quarterback Ian Book have transcended the typical restrictions of the coach-player relationship.

It’s dictated somewhat by age. Rees is just 26-years-old and Book is a junior academically. It has developed through shared experiences with Rees playing the position for the Irish just five seasons ago. It has evolved as two guys who have gone through many of the same things beyond the playing surface.

When Book takes the field Dec. 29 against Clemson in the Cotton Bowl, he’ll carry with him a snapshot of Rees’ life.

“I wanted to come back and give back to the quarterbacks at Notre Dame,” said Rees, who threw for more than 7,300 yards and 61 touchdowns for the Irish from 2010-13. “I wanted to give them something – a relationship -- that they could feel strongly about.

“We’re extremely close and a lot of people know that now. (Book) spends a lot of time in my office. We’ll go through football stuff, but there are times he wants to talk about classes or the NFL football game that was on the night before. We’ve just built a close relationship the last couple years.”

When Book arrived at Notre Dame from El Dorado, Calif., Rees was still working with the San Diego Chargers. Mike Sanford was Book’s first position coach with the Irish.

Rees quickly learned that he had a friend and a confidante in Rees, including one who had gone through the ups and downs of the quarterback position at Notre Dame under Brian Kelly. Book sat behind starter Brandon Wimbush and Rees lost his starting job to Everett Golson in 2012.

“I’m more aware of it now,” said Book of Rees’ experiences. “I didn’t grow up watching Notre Dame football. But just being able to talk to him and realize we were in similar situations was beneficial to my transition.”

The first thing Rees helped teach Book was how to work with the sometimes tempestuous Kelly, who placed Rees in the Notre Dame starting lineup 30 times and played him in 45 games from 2010-13.

“Part of my job is to make sure there’s seamless communication,” Rees said. “I understand Coach (Kelly). I know what he wants and what’s important. It’s my job to make sure it gets through to the quarterback.

“(Kelly) has done a great job of being clear and concise and helping develop (the quarterbacks) and being there for them. He’s been a ton of fun to work for. He’s been a mentor for me and I’ve learned a lot. It’s been cool to have a relationship as a player and as an assistant coach.”

But Kelly’s relationship with Rees couldn’t be like Rees’ relationship with Book. Kelly was the head coach. There was the age difference. The dynamics simply didn’t allow Kelly to relate to Rees the player the way Rees the coach can communicate with Book the player.

“He’s Coach Rees in the building,” Book said. “I call him Tommy sometimes. It’s a little weird, but he’s a pretty good friend of mine, so he’s probably okay with Tommy outside of the building.

“When you’re in this building, it’s business time, but we can still joke around. He’s taught me so much. He’s on me hard and pushes me every day. You definitely get the coaching aspect, but he’s a friend, too.

“I’ll go to his house and have pizza with the quarterbacks. To have someone there in your corner makes this whole journey enjoyable.”

While Book is living large these days as one of four quarterbacks in the college football playoffs with a recent Sports Illustrated cover shot to add to his fame, Rees had to oversee the process of developing a quarterback who wasn’t ready to play on a full-time basis as a freshman and sophomore.

Book stepped in as the starter in 2017 against North Carolina and helped lead the Irish to victory. He replaced Wimbush in the Citrus Bowl and helped orchestrate a come-from-behind win over LSU. But Book was far from the confident, well-schooled quarterback he developed into in late-September, October and November.

“The first things for Ian were mental,” Rees recalled. “We’re at ground zero here with general knowledge points, so we had to build that up.

“Consistency was a key thing, and then confidence. He needed reps and success on the field to build his confidence level up. Once he got that, you’ve seen the transformation to the player he’s been.”

Book recalls the decision to insert him into the starting lineup in the fourth game of the 2018 season against Wake Forest.

“(Rees) was like, ‘This is what you dreamed of doing,’” Book said. “He said, ‘You came here to be the starter. Don’t change anything. Just keep doing what you’re doing and embrace the moment. Just go out there and have fun.’”

It didn’t happen overnight. But with additional reps and more time in the Chip Long offense, things began to click for Book late in the spring. During August, he was, at the very least, on equal footing with Wimbush in terms of mastery of the offense. Then when the opportunity came calling, Book aggressively attacked the moment.

“A lot of the stuff he does during the week isn’t seen,” said Rees of Book. “But he’s constantly studying, asking questions, meeting with me…When you’re prepared and have done all the work during the week, it makes Saturdays easier. His preparation has put him in a really good spot to be successful.

“He’d been in the offense for a year-and-a-half. That’s helped. Plus, he’s a good player. You can see it during practice and you could see it during camp. He’s in control and that has resonated on the field.”

Rees will occasionally call up some old game film of himself for the entertainment value. But he’s not one to trumpet his successes as a player. Rees’ old game film is a learning experience for Book, not a trip down memory lane to feed an ego.

“There’s this tight end route we run and I wasn’t throwing it the right way,” Book related. “He was like, ‘This was my favorite route that I used to throw to Tyler Eifert.’

“He dialed it up in a minute and then I was like, ‘It makes sense.’ We’ve hit it in game (to Cole Kmet vs. Northwestern). Those learning moments are huge.”

Book jokes that it’s no coincidence that the old film Rees shows of himself are the good plays. But again, Rees is not one to pat himself on the back for his past accomplishments. Rees’ experiences are gold for Book.

“His memory is unbelievable,” Book said. “He’ll know the game and then go back and find it. The best thing about learning from someone who played here is he knows this is what happens when you do it like this.”

Rees has a laundry list of Book assets on the tip of his tongue.

“His temperament impresses me,” Rees said. “He’s a confident kid. Nothing really rattles him, which is impressive for his age and where he’s playing. His development mentally has been the reason he’s played so well. He’s worked at the learning part of it, which has been pretty cool to see.

“He’s a smart kid. As you play, it starts to come quicker and easier. He’s played well for us. He’s led the team well. The way he’s handled everything has been impressive. He’s played at a high level and he’s handled a lot of things thrown at him.”

The friendship and respect between Rees and Book is yet another reason why Notre Dame is where it is – playing for a shot at a national championship.

“We have a lot of similarities and mutual interests,” Rees said. “Last year, he identified me as someone he could trust. He knows that whatever he needs, he can come to me and have an advocate and someone with his best interests in mind.”

“He’s done a lot for me,” said Book of Rees. “I can’t give him enough credit. I feel real fortunate to have him as my coach.”