Sienna Miller gives birth to baby girl with boyfriend Oli Green

Pair were seen with newborn for the first time this week

Actor Sienna Miller has welcomed a baby girl with her boyfriend Oli Green.

The 42-year-old and her boyfriend, a 27-year-old fellow actor, were seen with their newborn for the first time on Wednesday during a walk in west London.

Wearing a khaki overcoat over a denim jumpsuit, the American Woman star was pushing her daughter in a £3,300 Artipoppe baby carrier.

Miller’s pregnancy was revealed in August, when the BAFTA-nominated actor was photographed with a baby bump on holiday in Ibiza.

This is her first child with Green, whom Miller began dating in 2021. She also shares a daughter, Marlowe, now 10, with her former partner Tom Sturridge, 38.

She previously opened up about the pressure to have more children in her 30s, but said that the pressure “dissipated” since turning 40, when she froze her eggs.

Sienna Miller with boyfriend Oli Green (Getty Images)

[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,” Miller told Elle UK.

“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.”

In an interview with British Vogue in December, when Miller announced she and Green were expecting a girl, she spoke about her insecurities about being an older mother.

“I’d love to get to a point where I didn’t feel the need to make a joke of my being older and having a baby, to show I’m in on the joke,” she said.

“I was very fortunate. I wasn’t necessarily trying to get pregnant. This happened as a total surprise and biologically was something I was able to do.”

She added: “I think people are comfortable with a way of living that has existed for many years, which is very misogynistic and patriarchal.

“Like me being the older woman in a partnership with a younger person or being pregnant over 40 and that that’s irresponsible and poor child and it’s such double standards.”

Miller also reflected on the age gap between her and Green, who stars in the latest season of Netflix’s The Crown, adding she has never been able to “legislate on matters of the heart”.

Acknowledging the idea that Green may one day want to be with someone closer to his own age, Miller said that specific insecurity “cuts both ways” in their relationship.

“For Oli, it is real that I might want to be with someone older,” she explained.