HE is the first, and probably the most important, arrival of the Ronny Deila era at Celtic.
Many faces will follow that of John Collins into Parkhead over the coming days and weeks as new boss Deila puts his stamp on the club.
But the appointment of the former Hoops midfielder will set the tone of things to come and could determine Deila's destiny as Celtic manager.
Having decided against bringing in his management team from former club Stromsgodset to Glasgow, the Norwegian has turned to Collins for advice and help as he settles into life at Parkhead.
Collins became the front-runner for the No.2 position even before Deila was officially unveiled as Neil Lennon's successor, and the deal to appoint the former Scotland star was completed last week.
The pair looked at ease with each other as they posed for pictures at Lennoxtown and both have spoken enthusiastically about working together and the challenge that awaits.
Deila, of course, will have the final say on matters, but Collins should prove to be a useful confidant as he becomes accustomed to Scottish football, as well as the workings of the Parkhead club.
One man who knows more than most about the role Collins will have to play is Murdo MacLeod, who performed similar duties as assistant to Wim Jansen as the Dutchman arrived from his homeland to guide Celtic to their first title in 10 years in season 1997-98.
"It is all about the partnership," MacLeod told SportTimes. "The manager and assistant manager have to gel well and they have got to have a good relationship.
"Sometimes when you appoint a manager he brings in an assistant manager and a coach with him and it is unusual that Ronny has not brought anyone with him from Norway.
"Having decided on that course of action, it was then up to him to meet with the candidates and make his choice.
"John is the man who has been appointed and I am sure the two of them will work well together. It is a great opportunity for the two of them."
With his studious approach to the game, it shouldn't take Deila long to assess his new group of players ahead of kick-off for the Premiership campaign in August.
But the role of Collins will be crucial in ensuring Celtic's third foreign boss fully understands what he has signed up for by swapping security at Stromsgodset for life in the fast lane of Scottish football.
MacLeod found himself in the position of right-hand man when Jansen was named as Tommy Burns' successor in the Parkhead dugout in 1997.
Within months, the pair had lifted the League Cup and their finest moment would arrive at the end of Jansen's only campaign at the helm, as the Hoops denied Rangers 10-in-a-row.
Deila arrives at Parkhead with a far different challenge as he looks to continue where Lennon left off and claim a fourth straight top-tier crown - and MacLeod reckons the presence of Collins should help smooth the transition for the new boss.
"There are a lot of things that Ronny won't know anything about and it is great that John can help him," he said.
"That is so important. John has been here as a player and knows what the club is all about. He knows the Celtic team but also the opposition, the grounds, what is expected at Celtic Park by the fans. Having him there will help Ronny settle in.
"Wim picked up so many things early on, he was a football man and a fantastic coach.
"He had the players going right away and really settled into Scottish football.
"He won his first trophy before the end of the year and that was a massive boost for the club and the fans. If Ronny can follow that then he will be off to a great start."
The appointment of Deila earlier this month caught many by surprise after a host of big names were linked with the Hoops top job, and his decision to place his trust in someone he has previously never worked with could be seen as a risk.
However, the pair appear to have similar views on how the game should be played and both place major importance on the next generation of stars nurtured through the ranks.
MacLeod, though, knows it is points and silverware that will determine how their legacy at Celtic Park is viewed.
"No matter who you bring in and what manager you are, everyone wants to play good football and has to play winning football," he said. "I have yet to hear any manager come in and say 'I will play the long ball'.
"That isn't a choice at Celtic. Celtic teams, no matter who they are playing against, they have to get forward, score goals and win games."