Sienna Miller’s ‘secret’ beauty product is just £13 on Amazon

Sienna Miller has revealed the beauty product she uses to get 'great skin' - and you can snap it up today for just £13 on Amazon.

Sienna Miller's effortless boho style has made her an icon when it comes to summer outfit inspiration, with her recent white jeans and raffia tote bag combo being the ultimate summer look, but her practical beauty secrets are must-haves for all year round.

Now we've all fallen in love with the humble and hydrating lip staple she swears by, and are keeping our nails healthy with her go-to rose-infused nailcare , there's yet another underrated beauty product she's now got us desperate to buy  - and she says it's the 'secret' to getting 'great skin.'

Speaking to Harper's Bazaar , Sienna revealed that she uses a niche French pharmacy product that keeps her skin smooth and glowing. The A313 Vitamin A Pommade by Pharma Développement is a surprisingly affordable retinol cream that you can buy over the counter in France - or on Amazon if you're anywhere else.

Pharma Développement A313 Vitamin A Retinol Cream: £13.35 | Amazon

Full of skin-loving active ingredients, this retinol cream not only gives a healthier and fuller appearance to skin, but also moisturises and draws much-needed water to the skin's surface, reducing wrinkles and sagging skin.

"This is a really fantastic secret," she said. "It's called A313 and it's a French retinol that you can get over the counter. Alexa Chung told me about it and she's got the most amazing skin. It's described as the French girl secret to great skin, so we all need that."

While there are a whole host of retinol creams and serums for every skin type , the A313 cream is a great option for those just beginning to incorporate the potent ingredient into their skincare regimes. This is because, instead of using a pure retinol, the formula contains retinyl palmitate, which is a combination of retinol and the fatty acid palmitic acid, meaning the cream is more on the gentle side though still works brilliantly to stimulate skin cell regeneration and collagen production, reduce wrinkles and sagging skin, and prevent hyperpigmentation as retinol usually does.

The cream is designed to be applied at night, with it's other ingredients helping skin to retain moisture and slow the signs of ageing.

RRP: £13.35

It's not just Sienna who is a fan of the French cream. Shoppers on Amazon are raving about it's 'miracle' effects, with one writing, "This cream really does work. You only need a little on super dry skin twice a week but the results can be seen the next day. Smoother and brighter skin."

Another added, "I use this every other night at the minute along with retimax on the nights off, and my skin has never felt and looked so good."

If you're planning on using any type of retinol on your skin, make sure to read up on the 5 mistakes you're making when applying retinol and learn how to use retinol to achieve the best results and avoid irritation.