Former St Andrews College and New Zealand test player Paul McEwan gave his former school team a batting lesson both on and off the pitch in a recent game.
So O'Leary will be in illustrious company during the April 13-24 tour.
Last year, O'Leary captured 54 wickets at an average of 11.73 - his best figures against Rathkeale College 7/28 including a hat trick in that two day match where he claimed 12/46.
This year, he is sitting on 24 wickets with a best of 5/15 against Christ College.
O'Leary is also developing as a handy big hitting lower order batsman with 46n/o to save the game against Wellington College as a major highlight this season.
He with little interest in the game at Kiwi Cricket and progressed to hardball with Marist Junior Cricket Club.
"I couldn't hit the ball, and couldn't bowl either at that age. I only went a few times because mum and dad made me," O'Leary recalled.
"I got sick of being rubbish. When I went to Huntley, the only summer sport I knew was cricket and Mark McAlly coached me in the seconds. I didn't progress further than the seconds at Huntley. I captained the Collegiate Colts B in Year 9 under Mark Wilson, I opened the bowling, kept and batted at three.
"It was great times and good banter, and I made very good friends at Collegiate through cricket. My parents persuaded me to take my cricket seriously and I worked really hard on my technique in Year 11 with Dilan Raj.
"The training was really tedious at the time, but I look back now and believe that's what has got me this far. If I had been at a bigger school, I probably would not be playing cricket now."
Being at Collegiate O'Leary has had the opportunity to learn from Level 3 coaches and former first class players.
"The two day fixtures, grass facilities and coaching has really helped me develop my all round game. I still have a lot to do, but I have the coaching support around me if I want to go far in my cricket.
"Barry Touzel was my first 1st XI coach and he created a great team environment. We were a fairly young side then. Dave Berry took over and thought me how to create pressure, have belief in myself and keep things really simple.
"Warren Marr is my current 1st XI coach and we are working on strategies to work batsmen out. Dilan has been with me throughout and we work together to develop a technique that's right for me."
Raj was also O'Leary's coach in the CD Under-17 side for the last two years.
"I really enjoyed that environment and now I'm looking forward to learning from Gary MacDonald (ex Canterbury) and Paul McEwan (ex NZ) on the Willows tour. The side aslo includes a number of NZ U18 players.
"I played against Ben Smith on the weekend and he was the last Collegiate cricketer to go on a Willows tour. He went to India but he gave me a lot of useful tips on touring the sub continent".
The touring side will play seven matches in Sri Lanka before facing a selection team on arrival in in Singapore on Anzac Day.