Tomorrow, he will be running beside Usain Bolt (or probably behind) and can barely contain his excitement at meeting arguably the greatest athlete the world has ever seen.
"I've still quite amazed that it is going to happen to be honest," says Millar. "Once I heard he was coming here, I convinced myself that I would make it happen [to see him] but training with him will be unbelievable.
"I've been thinking about questions for ages but I still don't know what I am going to ask him. There will probably be so many things going through my brain."
Millar might sound a bit like an over-excited boy band fan but his enthusiasm is understandable.
Bolt sits alongside Lionel Messi and probably just above Kobe Bryant as the most recognised sporting figures on the planet and the Jamaican confirmed his sporting excellence by defending his three Olympic gold medals in London under immense pressure.
His visit is a huge boost for New Zealand athletics, whose sprinters often ply their trade in anonymous and unrewarding circumstances.
"He is an entertainer as well as an athlete", says Millar. "People have criticised his methods and say he should be more serious when he prepares for races but he has his own way and it works."
Millar hopes that meeting Bolt - and sharing the track with him - can be the springboard towards his own lofty goals.
The 20-year-old Tauranga native, the fourth fastest Kiwi of all time, wants to become the first from these shores to run under 10 seconds (his personal best is 10.36s; the national record, set in 1994 by Gus Nketia, is 10.11s). Millar also wants to win a Commonwealth Games medal and make an Olympic final.
"Hopefully meeting Usain will help with the realisation that things are possible," says Millar, "and make it easier to train, set goals and achieve them. There is no reason why I can't; I'm doing all the right things and making good gains in training."
A former hockey player, Millar was always the quickest on his team and switched to athletics when he was 13 "to see what it was like to run really fast".
A product of the Papamoa Athletics Club, when not studying, he spends countless hours training, often with national team-mate Caley Harman.
Meanwhile, Bolt's trip is not quite at the farcical levels of Eva Longoria's visit last week, but is shrouded in security.
Aside from the athletics session, Bolt will also be practising with the Breakers as they launch a sponsorship deal and meeting staff at Frucor Beverages, an Auckland juice manufacturing plant.
