"I think I share a similar taste in clothes with her, that's why I find her so inspiring, elegant and she's just beautiful."
The 43-year-old's husband was enlisted to pick up a pair of $550 black Russell & Bromley boots when he visited London last year.
Catherine frequently wears the same style boots, including memorably when she was discharged from London's King Edward VII where she was being treated for acute morning sickness in December 2012.
Tan has also shipped over a pair of Catherine's favoured $600 LK Bennett patent black pumps from the United States.
To keep up with the latest royal garb, Tan follows the popular What Kate Wore page on Facebook and clicks through to the website daily.
The website has as many as 43,000 unique views on a day when Catherine steps out at an official engagement.
"I've tried to get stuff that she wore from eBay, but in the end I just didn't have the time and couldn't be bothered," said Tan.
"I do look through all the websites when she buys from Zara and places like that but they're always sold out. It's expensive to be like her, I tell you."
Tan will miss out on seeing her style icon in Dunedin on April 13, but has instead spent $1000 on changing flights for a school trip to China with her children two days earlier.
"I've changed my flights so I'll get to Auckland a bit earlier so I'll be able to go to the Auckland tour and go to China later that night," she said.
"My husband says you're not guaranteed to see her and I said that's the fun of it, isn't it. My reasoning is when are you going to see the next [future] Queen of England again."