Credit: Mike Marsland/

After a six-year run, Sienna Miller and her sister Savannah Miller announced Wednesday that they were leaving Twenty8Twelve by S. Miller.

"We've had a brilliant six years at Twenty8Twelve and are now looking forward to new pastures. We wish the brand the best of luck for the future," the Miller sisters said in a statement.

Twenty8Twelve, which stems from Sienna's birth date, will continue without the co-creative directors and will change the label to Twenty8Twelve London come fall, Women's Wear Daily confirms.

"We’ve had a great partnership with the Miller sisters," Nish Soneji, managing director of Twenty8Twelve, told WWD. "That vision, along with the uniquely British style the collection has become known for, will continue under the direction of the Twenty8Twelve design team."

In early January, it was confirmed that Sienna, 30, and her boyfriend of one year Tom Sturridge are expecting their first child. Perhaps the "new pastures" will include either maternity wear or baby clothes?