Pregnant Sienna Miller Keeps Her Baby Bump Under Wraps in Chic Oversized Ensemble

Pregnant Sienna Miller concealed her baby bump in a chic, oversized ensemble while out at a special launch for her fashion designer sister on Monday.

Posed in front of a black step-and-repeat at the London launch of Vivere by Savannah Miller at Luci in London, the radiant-looking actress, 41, wore a floor-length, charcoal grey skirt and a white blouse worn untucked under an oversized black blazer.

On the website, the womenswear collection features an array of "quiet luxury" contemporary pieces, which is exactly the look that Miller pulled off.

With her long, blonde hair worn down in her signature wave, Miller, in minimal makeup, appeared relaxed, with a soft, close-mouthed smile and her hands tucked in her calf-length coat.

In August, PEOPLE confirmed that Miller is pregnant and expecting her second baby after she was photographed in a bikini with a growing bump while on vacation in Ibiza.

Though Miller was covered up on Monday, she showed off her baby bump in September in a striking two-piece outfit while walking the red carpet at the Vogue World Show, kicking off London Fashion Week.

The American Woman star wore a cropped white, long-sleeve top that stopped just before her exposed stomach, pairing the piece with a voluminous white skirt.

Earlier this month, the British star's sister Savannah, 44, shared photos from her younger sibling's shower on Instagram, writing, “Last night we showered @siennathing in love in preparation for the most exciting arrival. It was pure magic.”

Savannah added, “I can’t wait to meet the newest member of our family 💕🌸🩷🌸💕🌸🩷🌸💕.”

Surrounded by her near and dear, the designer shared photos of Miller opening some of her gifts for her baby-to-be, as well as shots of some of the shower’s other guests, including Miller’s boyfriend, actor Oli Green, 26, and his brother, Sam Green, as well as the sisters’ mother, actress Josephine Miller.

The pink-themed décor was dressed with impressive balloon displays, a flower crown for Miller, and several pink-centric bouquets. There was also a nail art station for guests.

Though fans naturally think Miller is having another girl (she is already mom to daughter Marlowe, 11, whom she shares with her ex Tom Sturridge), MIller has not yet commented on the sex of her baby.

Miller has been dating Green since 2022 and has previously opened up about the "pressure" to grow her family after turning 40. In a 2022 interview with Elle UK, she discussed the topic and revealed that she’d had some of her eggs frozen.

"[The] pressure... [about] kids, and should I have more, and why haven’t I, and all of that, which is a really loud noise. Biology is incredibly cruel on women in that decade – that’s the headline, or it certainly was for me," she shared.

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Miller has been outspoken about her love of being a mom over the years. When Marlowe was 3, she reflected on how her daughter had changed her life, telling Marie Claire that motherhood was “the most profoundly, deeply affecting thing.” 

“I didn’t feel I had proper roots till I had her," she said.