The rocker took to her Instagram.com account on Monday (28Jul14) to break the news to fans and introduce her first child with her therapist husband Josh Hartzler to the world.
She shared a snap of herself cuddling the newborn in her hospital bed, and in the accompanying caption, she wrote, "Our little cub, Jack Lion Hartzler, is here.
"I have never known the depths of my heart till now. The world just exploded into technicolor."
The couple wed in 2007.