Revealed: Kate Middleton's secret for glowing skin

Kate's glowing skin can be credited to one simple beauty hack. Photo / Getty

It is rare to see the Duchess of Cambridge step out with a hair out of place let alone a blemish on her skin with her visage looking remarkably glowing time and time again.

And while the Duchess, 35, is bound to have access to a myriad of high-end skin care, her makeup artist claims that there is one bargain tool you need to invest in to achieve the royal's dewy skin.

Arabella Preston, the beauty guru who taught the Duchess how to do her wedding makeup, has revealed the "necessary" product in a new interview - and chances are you already own one.

According to the Daily Mail, Preston revealed that a flannel "is an essential part to making sure you wash your face cleanly".

"More gentle than any motorised cleanser brush, the right flannel will allow you to cleanly wipe makeup and dirt from your skin and gently exfoliate."

Preston gave the Duchess of Cambridge makeup lessons before her wedding in 2011, while other high-profile clients include Daisy Lowe and Lily James.

The Duchess famously did her own makeup for the big day despite two billion eyes upon her as she walked down the aisle at Westminster Abbey.

Kate famously did her makeup at her own wedding. Photo / Getty

With Preston's guidance she sported stronger eyeliner than usual with the sockets shaded with a grey taupe shadow.

As well as investing in a wash cloth the Duchess of Cambridge is said to be a fan of rosehip oil when it comes to caring for her skin.

According to US Weekly, she slathered Trilogy's Rosehip Oil on to her skin while pregnant with Princess Charlotte.

"Kate is very cautious of products and treatments," a source told the magazine. "Baby's health comes first.

"Kate continues to use rosehip oil in her daily skincare regiment. She loves the effect is has on her skin. [Her mother] Carole [Middleton] is also a fan."