FILE PHOTO: Kate Middleton waves as she arrives at Westminster Abbey for her marriage to Britain's Prince William, in central London. Picture: Toby Melville/Reuters

The perfume Duchess Catherine wore at her 2011 wedding is still out of stock - six years on.

Sales for White Gardenia Petals by Illuminum have been a huge hit ever since the Duchess of Cambridge wore it when she tied the knot with Prince William and even a number of years on, it is still proving tricky for royal fans to get their hands on the much sought after scent.

A description of the product reads: "White Gardenia Petals eau de parfum is a delicate, refined scent, evocative of summer ambience. Featuring a floral bouquet of lily, jasmine and ylang-ylang on a base of amber wood, this intoxicating fragrance will entice the senses of both men and women alike."

Whilst Michael Donovan, a spokesman for Illuminum, had said at the time: "There's been a phenomenal response. Orders have come in from dozens of different countries, but most of our customers have come from the U.S. It's charming to think that so many people abroad are interested in the wedding."

It comes after Duchess of Cambridge's hairdresser Richard Ward revealed that Catherine was very "calm" on her wedding day.

He said: "I have some incredible memories of that day. When she walked back into Buckingham Palace and her hair was all still in place, I cannot tell you the relief we all felt! I've seen brides far more nervous that Catherine! She was fantastic - she kept us calm, not the other way round!

"I wanted to show Kate the back of her hair [getting ready at Clarence House for the evening party] and I was struggling to walk with this 500-year-old mirror. He just said, 'Let me give you a hand.' And I said, 'No, no, honestly.' But he took one end and I've got the other and we're shuffling along with this mirror - he's great, he really is. It was the most incredible experience and I'll never forget it."