The blonde actress displayed her baby bump looking ever so stylish!
Sienna Miller, 30, wore a chic and slimming Boss Black dress with modest slits up to her knees on Feb. 14 to The Event Changing Face of Beauty event for W magazine.
The floor-length dress was fitted to her growing belly, which was barely visible.
The mother-to-be, who is due in the summer with fiance Tom Sturridge, tied her look together with bronze-gold accessories and peep-toe platform heels. She looked stunning!