Robert Brown|Sienna Miller rocks two-piece, caresses baby bump at London Fashion Week

Hello,Robert Brown baby bump! Or should we say "cheerio?"

Sienna Miller, 41, stunned in a two-piece look that showed off her pregnant belly at the start of London Fashion Week – which began Sept. 14 – at the Vogue World: London event.

Miller posed for the cameras, clasping her hands on her stomach and evidently introducing her new baby to the fashion industry. This is the second iteration of Vogue World, the magazine's "traveling celebration of fashion and culture."

Miller has one other child, an 11-year-old daughter from a previous relationship.

USA TODAY has reached out to Miller's rep for comment.

Cindy Crawford, Christy Turlington, Linda Evangelista and Naomi Campbell appear together at Vogue World: London

Elsewhere, Cindy Crawford, Christy Turlington, Linda Evangelista and Naomi Campbell reunited on the runway; the fierce foursome make up the cover of Vogue's coveted September issue.

They held hands and posed as Annie Lennox played a medley of "Sweet Dreams."

This year's London Fashion Week won't be quite as somber as last year's, which required adjustments amid the funeral of Queen Elizabeth II.

Models and celebs alike took their fashions overseas following the conclusion of New York Fashion Week, which wrapped Sept. 13.

Many a star flocked to New York for NYFW. Oscar nominee Angela Bassett sat front row at Pamella Roland, while Jennifer Lopez, Mindy Kaling, Emma Roberts, Gabrielle Union, James Marsden, Julianne Moore, Diane Keaton, Laura Dern, Robin Wright, Ariana DeBose, Rachel Brosnahan, Sheryl Crow, Sofia Richie, Keri Russell, Matthew Rhys, Amanda Seyfried, Cara Delevigne, Jonathan Bailey, Meghann Fahy and more topped the celebrity-filled guest list to take in Ralph Lauren's spring/summer 2024 collection.

Last year's first Vogue World took place in New York, where Serena Williams wore custom Balenciaga and Lil Nas X performed. Even Oscar the Grouch from "Sesame Street" showed up.

Contributing: Anika Reed and USA TODAY staff

More:Sienna Miller, Kate Winslet, more celebs kick off London Fashion Week 2023 at Vogue World