Fletcher called his father on Tuesday to tell him he had been named in the 23 for the second Lipovitan-D Rugby Championship Test in Johannesburg on Saturday (SA time).
But that was only the first surprise of the week for Newell Senior.
"And then he rang me this morning [Thursday] fairly early, I was just about to get out of bed, and he said, 'You'd better pack your bags.'
And I was like, 'What?' it didn't really sink in that quickly.
"He said, 'We're getting you over for my debut'. It was pretty emotional.
"It was very overwhelming. We talked for a wee bit. I did say, 'I have to go because I'm getting too emotional now'.
"He's organised it all himself with the All Blacks' team. It's pretty surreal really. So in the morning I'm off."
Arnold will be in Johannesburg 24 hours before kick-off.
In looking at Fletcher's career, he thought if he made the All Blacks, he would debut in a home game, but Ellis Park would be something special.
"Seventy thousand South African people and you're debuting, it doesn't get much bigger, and as a parent it's pretty incredible," he said.
Watching his son grow up and through the emotion of losing his mother at 15, Arnold said Fletcher had always been cool and calm and didn't say a lot.
The family had carried on through that time. Fletcher had a small tattoo on his arm in memory of her.
"But when he makes comments about rugby, he knows what he's talking about."
"I did ask him the other day if he were to get a run how he thought he would go, and he's not phased.
"I'm sure it will be emotional on the day, and probably has been sinking in, but he wouldn't do it otherwise."
Arnold said Fletcher had always been driven with his rugby. He had progressed through the representative grades and excelled at each level.
Newell Senior's pride in his son's achievement was reflected in him putting a hand-made sign up on his property (pictured below) alongside State Highway One, Leithfield Beach, informing the public of his Fletcher's new status.
"If they don't know who he was, they do now, and I'm pretty sure after the game everyone will know him."