The "Pretty Little Liars" star surprised fans with the baby news on Friday (04Jun21), when she shared a black-and-white photo of herself holding a baby girl and planting a kiss on her head.
"Ms Elliot Rowena Adams joined us on May 15th under the wildest of circumstances," the new mum captioned the image.
"A whole new ERA for this family. Welcome, my love. (photo) by papa @halfadams (sic)."
Proud dad Adams also took to Instagram to post his own picture of the tot clutching his finger.
"+1.....Welcome to the funhouse, Ms. Elliot Rowena Adams," the "Suits" star wrote. "May your life be as unique and exciting as your arrival."
The couple, which didn't announce Bellisario's pregnancy, stopped short of revealing the story behind the baby's arrival, but their famous friends were quick to offer up their well wishes.
Little Elliot joins the stars' two-year-old daughter Aurora.
Although the couple never officially announced her latest pregnancy, Patrick J. Adams might have given a clue when he paid tribute to Troian Bellisario on Mother's Day last month. The actor posted a playful picture of his wife sitting in a baby buggy while covering her belly as little Aurora adorably tried to push the stroller.
He wrote, "You are all places at once, doing more things than I can count, keeping us alive and teaching us to smile and laugh through all of it. I can't pretend to understand how you do everything you do and with such grace and kindness and humor. But I'll never stop being grateful for every single second of it. Thank you @sleepinthegardn for pushing us all up the hill. Here's to letting us push you for a minute. Happy Mother's Day."