"Apparently she thought Labor Day weekend meant LABOR day weekend… Look who showed up 3 weeks early!" Ruah posted to Instagram on Wednesday, along with a sweet family photo. "On September 4th we welcomed little Miss Sierra Esther Ruah Olsen!"
"She entered the world in her own way- breeched!" the 32-year-old actress, already mom to 2-year-old son River Issac, explained. "I was a good candidate to deliver her naturally so I needed to find a doctor in LA who would know how to do it. Fortunately I found one of the few."
"Healthy & happy mommy & baby walked out of the hospital 24 hrs later," she wrote. "I had an OB and doula assisted birth at Cedars Sinai, and the #love and #support of my wonderful #hubby❤ This photo is the perfect representation of everything I've ever wanted."
Ruah’s sister-in-law, Sarah Wright Olsen, couldn't help but gush about the family's new addition.
"Yay!! So excited to repost this news!! So ridiculously proud of this strong beautiful mama! So grateful to have her as my family," she posted alongside Ruah's family pic. "Welcome to the world Sierra! Thank you to the team that assisted in this incredible breech birth!"
Olsen, who is married to Ruah's on-screen lover, Eric Christian Olsen, welcomed her own daughter, Esme Olivia, just four weeks earlier.
And while their relationship might get tricky, Sarah and Daniela couldn't be closer in real life!