'My focus was very much on the next game in the Junior World Championship against Argentina and getting myself and the team ready for that, so this was an incredible honour for me and something I never expected."
The 19-year-old Leinster Academy player made his senior debut for the province last December and has already had a season to remember, having captained the Ireland Under-20s to the Six Nations title.
Rhys and older brother Ciaran, who has also played for the Ireland U-20s and Leinster, are sons of former Leinster coach Mike Ruddock who most notably guided Wales to a Grand Slam in 2005.
Relishing the opportunity presented to him Down Under, Rhys added: "We were unfortunate in our games in the Junior World Championship, narrowly losing our opening two games against France and England, and while I would never have wanted to miss out on leading the guys in the next game, this was just something that surpassed any of my expectations.
"The season went really well for the Under-20s with our Six Nations Championship win and I felt I was going alright in terms of my own performances.
"My ultimate aim is obviously to represent Ireland (at Test level) and I certainly didn't think that I would get a call-up to the senior squad so early in my career.
"My focus now is just to learn as much as I possibly can and make sure that I don't let the opportunity pass me by.
"I trained for the first time this afternoon and the welcome from the guys was great. I just want to train hard over the next couple of days and if the coaches feel they want me, I am ready to do whatever they need me to do."
Declan Kidney's squad are in Rotorua ahead of Friday's clash with New Zealand Maori. The Ireland team and replacements for that game will be announced on Tuesday (1.15pm New Zealand time).