Sienna Miller: Twenty8Twelve Look Book!

Sienna Miller strikes a pose in this photo from the Twenty8Twelve look book.

Nylon got a first look at the 29-year-old British actress modeling the latest pieces from the clothing line, which she works on with older sis Savannah.

One of the brand’s newest additions: a pair of jeans that are both skinny and flared!

FYI: Sienna has donated a pair of shoes to the Small Steps Project, a charity aimed to raise awareness and help children working on some of the world’s biggest landfills.

Heels from Sarah Jessica Parker, Rachel Weisz, Kristen Davis, and other celebs will also be auctioned off at the Royal Society of Medicine on Oct. 12 as well as an online auction.

For more sneak peeks of the new Twenty8Twelve collection, check out NylonMag.com!