Celebrity Parents Sienna Miller Shows Off Baby Bump in Fall Fashion Campaign The pregnant actress is the face of iconic British brand Marks and Spencer's new collection By Clare Fisher Clare Fisher Clare Fisher is an editor for PEOPLE with over 15 years of experience in journalism. She has written for publications including OK! Magazine, The Mail on Sunday, Good Housekeeping, The Times and Red Magazine. People Editorial Guidelines Updated on September 6, 2023 11:36AM EDT Close Photo: Richard Young/Shutterstock Pregnant Sienna Miller is stepping out in style! The actress — who is currently expecting a baby with boyfriend Oli Green — showed off her chic maternity style on Tuesday night when she attended the VIP drinks reception for Marks and Spencer’s new Fall campaign at the Mall Galleries in London. For the event, Miller — who is fronting the campaign — wore a black three-piece draped suit which was teamed with eye-catching red earrings, with her baby bump just visible beneath her black shirt. Her blonde hair was worn loose, styled into soft waves, while she opted for a neutral make up look. The pregnant star looked elegant on the evening. Richard Young/Shutterstock Sienna Miller Steps Out in Floaty White Dress Days Before Pregnancy Is Revealed For the new campaign, Miller, 41, has been photographed in a selection of fall attire from the brand, including a tweed blazer, chunky knit sweater and checked jacket, and recently spoke about her affinity to the British label. “I have always had a genuine love for Marks and Spencer, a brand that is part of the fabric of British life and holds special associations for so many people,” she said according to a press release from the brand. News of the actress and fashion icon's second pregnancy — she is already mom to daughter Marlowe, 11, whom she shares with actor Tom Sturridge — first came when Miller was photographed on the beach in Ibiza late last month, wearing a brown two-piece bikini that accentuated her growing bump. Miller's rep did not respond to PEOPLE's request for comment at the time. Miller is expecting her first child with Oli Green. Stephane Cardinale - Corbis/Corbis via Getty Sienna Miller Recalls 'Violently' Interrogating Five People in Her Life Over 'Selling Stories' to Press The actress has been dating her 26-year-old boyfriend 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 told the outlet. "Then I got to 40 and I froze some eggs. Having been really focused on the need to have another baby, I’m just like, if it happens, it happens. That kind of existential threat has dissipated." Miller shares 11-year-old Marlowe with Tom Sturridge. Arturo Holmes/Getty Images for NYFW: The Shows She also gave an insight into her parenting style in April 2020 when she spoke about the challenges of homeschooling daughter Marlowe during the coronavirus (COVID-19) global health crisis. In an interview with Vogue at the time, the star said, "Having to homeschool is a challenge, and it makes you greatly appreciate the people who teach for a living. They are making this system work in such an unpredictable and scary time." Never miss a story — sign up for PEOPLE's free daily newsletter to stay up-to-date on the best of what PEOPLE has to offer, from juicy celebrity news to compelling human interest stories. She added that while the experience was "overwhelming," she was "trying to bring in as much optimism as possible" to their home "and make the most of the time I get to spend with my daughter." "There's been lots of baking, lots of makeup, lots of swings," Miller said.