A light-hearted event in which the regular caddies get a day off and the players involved often recruit friends and family to carry the bags.
Amid some sniping out there at this magical marketing link-up between two of Ireland’s most famous men, here are 10 reasons why you shouldn’t begrudge Niall the walk around Augusta.
In 2007, the unknown Horan, then 14, caddied for former Boyzone star Keith Duffy.
"He was a shy kid but terribly nice, so at the end of the round I reached into my pocket and gave him a €50 tip. It made him very happy," said Duffy.
A golf day hosted by Horan at his home club in Mullingar in 2012 raised €50,000 for Duffy’s favoured charity, Irish Autism Action (IAA).
A regular on the course in his childhood, and a member since the start of his teens, the singer was honoured by the Westmeath club last year. His tweets suggested he was quite touched by the gesture:
“Thank you to everyone at mullingar golf club for making me an Honorary life member of the club! What a nice touch.”
“I’ve been a member of the club since I was 12/13, and to be awarded with this now is just incredible! Really much appreciated!”
“Thanks for even thinking about me.”
In 2013, Horan escorted Victoria's Secret model Barbara Palvin on the ultimate romantic date: the pair hit a few dozen balls at the TopGolf driving range in London.
Horan doesn’t need fancy surroundings to work on his long game. Celebrating another trip home, he tweeted:
“I love when I do sweet F all on my days off! Hit a few golf balls from my garden to a field today and that’s as exciting as my day is.”
"Loved Wentworth today with @TaylorMadeTour the new SLDR is sick! thanks for having me guys! #SLDR"
There are people out there keeping track of all this. And they are hungry for more.
MTV reports: “Niall and McIlroy have apparently been friends for years (they’re both Northern Ireland natives, meaning that yes, McIlroy also has that adorable Irish accent you love”