SIBLING design duo Sienna and Savannah Miller, aka the creative geniuses behind luxe label Twenty8Twelve, have revealed exclusively to VOGUE.COM that they are "so excited" to be preparing for their debut catwalk show at London Fashion Week in February.

Having launched to much fanfare for autumn/winter 2007-8, the label - which comprises all the clothes the designers would love to wear and just couldn't find anywhere else - already sells via two standalone London stores as well as through top retailers such as Selfridges, Matches, Harvey Nichols, Lane Crawford and Neiman Marcus. Putting a collection on the catwalk, however, is sure to catapult it into the global fashion spotlight like never before.

"Twenty8Twelve is now in its fifth season and we just felt it was ready to be taken to the next level," the sisters tell us of the move. "British Fashion Week is celebrating 25 years in 2009 and we are thrilled to be a part of this."

Expect more of the signature tailoring and oh-so pretty vintage dresses for which the label has become known; Savannah, who trained within the hallowed halls of Central Saint Martins, certainly knows her finishes while younger sister Sienna is almost - almost - as famous for her style as she is for her acting career.