The actress was dressed like royalty.
If, like us, you love keeping up with the Duchess of Cambridge's favourite fashion brands, then you'll know that Kate Middleton is a big fan of Self-Portrait.
In fact, the Duchess was spotted in a white Self-Portrait dress back in April, and it practically flew off the shelves. So, it's no surprise that lots of stylish celebrities have been following in the royal's footsteps and trying out the brand for themselves.
The latest celebrity to join the hype? None other than Sienna Miller.
That's right, the actress was just spotted wearing a light blue, knit midi dress by Self-Portrait to attend the red carpet premiere for The Sandman.
Sienna's dress featured a statement bow-shaped bodice and fluted sleeves, and she paired it with simple white heels and a matching white shoulder bag. Perfection.
Her exact outfit is still available to buy, and we happen to think that it would make the perfect wedding guest dress.
If you're looking for a more affordable alternative, we've rounded up some of our favourite high street versions below. Just keep on scrolling...
Get the look: Sienna Miller's blue knit dress:
We want them all.
