Actress Sienna Miller will make her debut at London Fashion Week next month with a collection co-designed with her older sister Savannah. Designs from Twenty8Twelve are due to follow big names such as Betty Jackson, Nicole Farhi and Christopher Kane on to the catwalk on February 22.

“Twenty8Twelve is now in its fifth season and we just felt it was ready to be taken to the next level.” Sienna’s quirky style has often made headlines. An outfit she wore to a New York party after the premiere of her film Factory Girl in 2007 was said to have started a trend for black pants over thick tights. The actress was also said to have sparked a rise in the sales of footless tights a few months later. On the Twenty8Twelve website, Savannah says her famous sister is great to “bounce ideas about with”. “Sienna has always been quite forward thinking in her approach to fashion so working with her is always great as she comes up with crazy ideas that I perhaps wouldn’t otherwise consider.”