Olivia Munn and John Mulroney were delighted to announce their baby news on Sunday.
The couple revealed they'd welcomed a daughter via surrogate on September 14 and The Newsroom star shared a beautiful post on Instagram.
Alongside photos from the hospital where the pair cradled their newborn and others once they brought her home to meet her big brother, Olivia wrote: "Méi June Mulaney came into the world September 14, 2024, the year of the dragon.
"I had so many profound emotions about not being able to carry my daughter. When I first met our gestational surrogate we spoke mother to mother."
She continued: "She showed me so much grace and understanding, I knew I had found a real-life angel. Words cannot express my gratitude that she kept our baby safe for 9 months and made our dreams come true.
"I am so proud of my little plum, my little dragon for making the journey to be with us. My heart has exploded.
"Méi (pronounced may) means plum in Chinese."
John also shared a post on social media. "Méi June Mulaney came into the world September 14, 2024, the year of the dragon," the comedian penned, before joking: "We stole so much stuff from the hospital. love my little girl so much."
They were inundated with congratulatory messages from fans, loved ones and famous friends.
Olive and John are already parents to Malcolm, two, who they welcomed in November 2021.
It's been a rollercoaster year for the family, with their wedding in July, and prior to that, Olivia revealed her "terrifying" breast cancer diagnosis.
She had a double mastectomy and underwent medically induced menopause.
After her initial diagnosis, Olivia had egg retrieval followed by breast reconstruction surgery.
She told People that being a mom to Malcolm helped her through her treatment.
"When I’m with him, it's the only time my brain doesn’t think about being sick. I'm just so happy with him," she said. "And it puts a lot of stuff into perspective. Because if my body changes, I’m still his mom. If I have hot flashes, I’m still his mom. If I lose my hair, I’m still his mom. That’s really what matters the most to me. I get to be here for him."