Geary posted a picture of herself wearing a pink sweater that reads "Baby Girl," with Mia in her arms. "My little love," Geary wrote, adding a flower emoji in the caption.
Mia was born on Feb. 22 via a scheduled C-Section, Entertainment Tonight confirmed two days later. The 41-year-old Thicke also posted a video of himself cradling the newborn, with her face away from the camera, to celebrate the happy news. "On 2/22 at 13:33 Mia Love Thicke was born. Thank you God and April Love," the "Blurred Lines" singer wrote on Instagram.
Thicke also has a 7-year-old son with ex-wife Paula Patton. The couple was married for 10 years before their divorce in 2015.
Thicke and Geary have been together for three years. According to PEOPLE magazine, they made their public debut as a couple at the 2015 Cannes Film Festival and announced this past August she was expecting a baby girl.
Just days before Mia was born, the 23-year-old Geary celebrated Valentine's Day by posting nearly-naked, sexy photos of herself on Instagram.
"I LOVE VALENTINES DAY," she wrote. "EVERY BODY IS BEAUTIFUL, TALL SHORT THICK SKINNY PREGNANT OR NOT, LOVE YOURSELF. Feeling confident is so important."
The couple have not tied the knot yet. In November 2016, there were rumors they were on their honeymoon after they poste their latest PDA-filled, sun-bleached photos. They even got each others' initials tattooed on their fingers to celebrate their second anniversary together. However, a source told PEOPLE at the time that they were just dating.0comments
While Thicke's personal life is on the upswing, his career is still on a bumpy road. Last week, a court upheld the 2015 decision in the "Blurred Lines" infringement trial. Thicke and Pharrell Williams were ordered to pay $5.3 million to the Marvin Gaye estate, since the song lifted from Gaye's "Got To Give It Up," reports The Hollywood Reporter.
Thicke also has not released a new album since 2014's Paula, which was dedicated to Patton. He has released four singles since then, including "Morning Sun" and "Back Together," but none have surfaced on an album.