Rickie Fowler is a friend and foe of Rory McIlroy and that's the way it will be for years to come.
The former Walker Cup rivals have taken their golfing tussles into the world of professional golf eight years after their first encounter in the 2007 match at Royal County Down.
Hatred and bitterness has no part in this relationship.
The desire to match and beat each other on the course is huge when the occasion demands. After that, they'll chill out and enjoy each other's company.
The recently crowned Players Championship winner and tournament host McIlroy took time out for a laugh and a joke in yesterday's pro-am when their groups passed each other on adjoining fairways.
Fowler's name added a little extra to the promotion and excitement around the Irish Open and joins McIlroy and Martin Kaymer for the first two rounds of the tournament at Royal County Down.
The 26-year-old turned pro in 2009, two years after McIlroy, so it took time for them to meet on Tour and have the opportunity to renew their friendship.
Once McIlroy extended an invite, Fowler did not hesitate to add the Irish event and the Scottish Open to his summer calendar.
His past experience on the Newcastle links was also a factor.
"Being able to help out Rory and his foundation, and getting asked by him to come over here and play, I didn't have to think about it at all," Fowler said.
"It's one of my favourite places to play that I've ever been to and being able to help out a friend. Like I was talking about, I feel like this is a good test as a tournament and obviously the course is amazing to me," he said.
The performance of both players will be carefully scrutinised once they tee off today. It's unlikely they will have a few quid on the outcome, but both players will be mindful of past occasions when they both edged into contention.
McIlroy has done better in these situations but is ever mindful of the potential threat Fowler can pose.
"The two previous tournaments Rickie had won as a professional before The Players, I finished runner-up in both of them.
"He beat me in a play-off at Quail Hollow and he beat me by six or seven in Korea a couple of years ago," said McIlroy.