The 24-year-old competed for Ireland at the 2021 European Championships and Tokyo Olympics before switching to Team GB in 2022 after moving to Scotland to attend the University of Stirling.
After making the switch, the Bangor swimmer had to sit out competition for a year before making his Team GB debut at the 2024 World Championships in Doha and subsequently earning his Olympic spot.
“I made the decision [to switch to Team GB] two years ago, and at the time it was quite risky because it’s a wee bit harder to get onto the Team GB team, especially in swimming,” added McMillan.
“No-one had really transitioned from Ireland to Great Britain in swimming anyway so I didn’t have anyone to talk to about it I guess, so it was quite a risky move at the time and I was quite unsure about the whole thing.
“Two years ago this was the ultimate goal. This was the dream and for it to actually come true, it’s pretty surreal.”
