Zac Brown Band's Clay Cook, his wife Brooke and their son Charlie are now a family of four: Brooke gave birth to their second child on Wednesday (Aug. 22).

Theron Maine Cook was born on Aug. 22 at 9:01PM, Cook reports on his Instagram account. Baby Theron weighed 7 pounds, 12 ounces, and measured 19.75 inches at birth.

"Mama and baby are safe and happy," Cook says. "I'm so lucky in this life."

Following Theron's birth, Cook also shared a video of Charlie, their first child, celebrating the arrival of his younger sibling. "When you find out that you're a big brother now," Cook captions the clip.

Cook and his family announced the impending arrival of their newest member in late January. Charlie was born in November of 2016; Cook and his wife have been married since 2014.

Baby Theron isn't the only new Zac Brown Band family member who's come into the world in 2018: Fellow ZBB member Coy Bowles and his wife welcomed their second child, a girl named Millie Mercy, in mid-February, while bassist Matt Mangano's wife gave birth to their third child -- their second son, named Mason Thomas -- in April.

Zac Brown Band have spent the summer of 2018 on the road for their Down the Rabbit Hole Live: Zac Brown Band 2018 tour.

Country Babies Born in 2018