"I don't think it has properly hit me yet how big a thing this is," he said. "It just seems a little bit surreal.
"When I was at school and I was daydreaming in a boring maths class, I was think about playing at Murrayfield against the best side in the world, and it just sort of happened within a couple of weeks.
"Everyone was together when the team was announced. It was just after the Romania game in the changing rooms at Murrayfield. I was just so excited I couldn't keep the smile off my face.
"I didn't phone anyone for a while because I wasn't too sure if I was dreaming or not, but I eventually phoned my dad.
"I've never been in this situation before so I didn't really know what to expect. Obviously when you are brought in you are hoping to play but I wasn't expecting anything.
"I knew that all I could do was keep training and take each day as it comes, so that was what I was trying to do."
As baptisms of fire go, the challenge facing Dickinson on Sunday must be pretty near the top end of the scale. New Zealand are the top-ranked team in the world and have been in devastating form in the tournament so far.
Furthermore, Dickinson is going to have to pack down against Carl Hayman - probably the best tight-head prop in the world at the moment.
To his credit, Dickinson is making a pretty decent fist of putting on a brave face ahead of what looks certain to be the biggest challenge of his rugby career to date. He did, however, concede that he is not entirely sure of what he is going to encounter.
He said: "It is a massive test, and I'm really excited about gauging myself against him. To better yourself you've got to play against the best players, so I'm looking forward to it."