Liev Schreiber is liev-ing the dad life.

The Ray Donovan star and girlfriend Taylor Neisen welcomed their first baby together, a daughter named Hazel Bee, he shared on Instagram Sept. 13. 

"So happy that Hazel Bee is finally here," Liev wrote. "She arrived early in the morning of August 27th and has been a dream every day since."

The 55-year-old added, "Mom and baby are both super happy and healthy. Thanks to all for the love and support."

The couple was first linked in 2017, when they were spotted out in New York City together. Since then, they've made a handful of red carpet appearances together, the latest being Ali Forney Center's A Place at the Table Gala in May. At the charity event, Taylor showed off her growing baby bump in a strapless purple gown.

Their new addition comes nearly three months after Liev's ex Naomi Watts—with whom he shares sons Kai, 14, and Sasha, 16—tied the knot with Billy Crudup at a Manhattan courthouse. For the occasion, the Mullholland Drive actress wore embroidered bridal gown by Oscar de la Renta, while her groom donned a navy blue suit with a white button-down.

Naomi captioned a June 10 photo of herself and her new husband, "Hitched!"

Liev and Naomi, 54, were together for 11 years before their breakup in 2016. "We're parents together, so we'll be together for the rest of our lives no matter what," the actor shared in a CBS This Morning interview two months after news of the split. "We're very close. Hopefully, that never changes and I don't think it will." 

In 2017, Naomi confirmed that she and Liev remain "on great terms" as co-parents.

"He's fantastic dad, a wonderful, wonderful man," she told Vogue Australia, "and we still want the absolute best for each other."

In fact, Liev and Naomi were joined by their respective partners for Kai graduation last year. In a group selfie posted to Noami's Instagram, Taylor, 31, and Billy, 55, were both seen smiling next to the former couple and their youngest son.

"Congratulations to Kai. Class of 2022," the two-time Oscar nominee wrote in the caption. "#modernfamily."