The hat designer, who opens his first shop in Glasgow's Italian Centre on Friday, credits the Duchess of Cambridge with making hats fashionable again.
He said: "It is that Catherine Middleton effect, especially for the younger customer.
"I think young women of 25 upwards feel that it is now acceptable to wear a hat to a wedding and they don't feel out of place or silly.
"A hat gives them confidence and it is another accessory that has not been utilised in the past. Until the last few years it was all about the bag, all about the shoe, but the hat is an exciting thing for them to accessorise with because it is a real statement."
The designer, who launched his millinery business in 2008, has established a key clientele that includes mothers of the bride, mothers of the groom, brides and racegoers.
He has also proved popular with celebrities as his hats have graced the heads of stars including Kelis, Roisin Murphy and Anna Dello Russo.
While he is thankful for the celebrity endorsements, his focus is firmly set on his ordinary buyers.
He said: "There have been key moments but I get more pleasure from seeing a customer wearing one of my hats, from an every-day woman wearing one of my hats."
While his hats are stocked in high-profile stores such as Harrods and Fenwick in London, he has resisted the lure to relocate there and sees Glasgow as crucial to the DNA of his brand.
This has led him to set up shop in an airy and light space in Glasgow's prestigious Italian Centre where customers can try on and buy designs from his ready-to-wear collection, which are displayed on vintage flagpoles, with prices starting from £80.
Alternatively, customers can opt to go for the bespoke made-to-order service and have a hat designed and handmade from scratch to their exact specifications.
Choosing the Italian Centre as the location for his first shop was a no-brainer.
William said: "We looked and looked for the perfect venue or shop unit and there was nothing quite right.
"Everything was either too large or in the wrong position or in a basement and I thought the Italian Centre still had that feel of a destination about it.
"I felt that it was tucked away and it still felt like a little gem. It felt like people were going to come and visit us, it felt like a destination shop rather than on a high street as we didn't really want that.
ANOTHER main reason was to be located close to the main high-end boutiques so we are right next to Armani, Cruise and everyone else."
Since launching his brand, Wiliam's hats have been featured in fashion magazines such as Vogue, Elle and Grazia but he credits being selected by renowned milliner Stephen Jones to exhibit at the Headon-ism showcase at London Fashion Week as his big break.
He said: "If it wasn't for Stephen Jones bringing me into Headonism at fashion week, I wouldn't be in this position.
"From his first invitation to exhibit at London fashion week, we had spoken to three major stockists in London and they ordered for spring/summer the following season, so without that invitation to exhibit, I don't think my business would be in this position to actually sustain what I am doing just now."
His signature hats feature oversized florals, leather details and unusual materials such as plastic.
They are striking, feminine and are created to make a statement and this is what Chambers loves about hats.
He added: "Regardless of if you are putting on a baseball cap or an occasion hat, you will be looked at.
"So I think that is what a hat does for someone, it gives them a sense of theatre and occasion."