Thomson tells people he recognises and responds to 20 commands - but she thinks it's closer to 25.
The pair met six years ago when Thomson's sister and brother-in-law who run sheep at Burkes Pass, between Fairlie and Lake Tekapo, had a ewe that birthed triplets but only managed to feed two of her lambs.
Thomson visited and tried to help the third lamb latch onto its mother - but she had no luck.
Then her sister had an idea: "My sister said to me: 'Do you want a lamb?' And I said: 'yes!'" Thomson said.
Life with Lucky took a bit of adjusting while Thomson juggled looking after the lamb and studying.
During the day, she would drop Lucky off at her sister's and pick him up again in the afternoon - until he grew too big.
Then she kept Lucky in her garden on a long leash before investing in an electric fence pen.
In his pen lies a bucket of water, a mini shed for sleeping, a football that he pushes around and a homemade jump for his tricks.
It's clear that Lucky enjoys spending time with Thomson and even ventures down to Burkes Pass in the back of her car for family gatherings.