British designer Savannah Miller has welcomed her fourth child, a baby boy, with her husband James Whewell.
The 47-year-old shared the first photograph of her newborn on Instagram on Saturday, two days after giving birth.
She posted an image of herself breastfeeding the baby, who was dressed in a striped baby grow.
"Tiny boy arrived safe and well on Thursday evening," Miller wrote. "I have no words for the deep and profound ecstasy of this time.... More soon but for now we soak up the bliss".
Savannah, who is the older sister of actress Sienna Miller, married Whewell in a "magical" ceremony in 2022, having met him six months after splitting from her first husband.
She is already mother to Moses, 21, Lyra, 18, and Bali, 14, from her previous marriage to Nick Skinner.
A complicated fertility journey
The couple announced they were expecting a child in March, following a "complicated" fertility journey. They have chosen not to disclose the method of conception, stating it is their child's right to decide whether to share that information.
When discussing the possibility of having a child together, Whewell told his wife he would be happy with whatever decision she made.
Following her announcement on Saturday, friends and followers sent their congratulations. Personality Tanya Burr wrote, "Congratulations!", while others left comments including, "Wonderful news," and "Hugeeeee congratulations, we can't wait to meet him and have play dates."
Another commenter added: "Hugest congratulations darling one!!! Sending you all the softness strength peace & power for this beautiful shapeshifting time."
Inspired by her sister
Miller recently revealed she was inspired to have another child in her forties after watching her sister Sienna embrace motherhood again. Sienna welcomed her second child with fiancé Oli Green, 29, in 2024, and had her third baby in May.
Savannah said her sister's attitude toward motherhood and life made her realise she could handle another baby, deciding she was "all in" when Sienna announced her third pregnancy.
Speaking to British Vogue about the decision, Savannah explained how spending time with Sienna's younger daughter changed her perspective.
"The longer I spent with my magical little niece, the more I realised how much I had changed since having Moses all those years ago," she told the magazine. "In my 20s and 30s, I had so much to prove to the world, and to myself; every day felt like a race that could never be won."
"Now, when I'm with Sienna's younger daughter, I feel a lot more present, all of my urgency replaced by a sense of how quickly the years pass, no matter how long each day feels," she said.
Miller realised she would be approaching parenting from a place of "much deeper wisdom" alongside a new partner.
"For so long I thought that having another baby in my 40s would mean beginning the motherhood journey all over again, but actually, I realised, I'd be starting from a completely different place this time," she explained. "When Sienna told me in 2025 about her third, it felt like a sign. If we should be so lucky for it to happen, I was in."
A shared pregnancy
When she announced her pregnancy in March, Savannah shared pictures of her baby bump and celebrated being pregnant alongside her sister.
"Our longed for miracle baby is joining the gang in August!" she said at the time. "To be able to relive the magic of pregnancy, with Jim, who is the most deserving and dedicated dad already to my three, is a profound and phenomenal gift."
She acknowledged the speed at which her children had grown up, saying that as her eldest approached his 21st birthday, she hoped to "slowly savour the innocence and wonder in every minute" with her new arrival.
"To be doing it all over again at the same time as my sister is the most delicious cherry on the icing on the cake," she added.
Miller admitted that synchronising their pregnancies was a deliberate choice.
"It was intentional on my part," she said. "I thought: 'If she's doing it again, at least I won't be in the trenches on my own. I'll join her... if I should be so lucky.'"
