According to reports from US Weekly, the newest addition will join 7-year-old Kingston and 5-year-old Zuma, who both take after their mother with their light blond hair.
Lately, the No Doubt frontwoman has been concealing any evidence with baggy tops or pants over the beginning baby bump.
Enjoying a rare long marriage in Tinseltown, Gwen and Gavin tied the knot back in 2002. In October 2012, the 43-year-old rocker told Marie Claire, "I really, really, really wanted one about two years ago. And it didn't work out. So...I feel good with what we've got. Everything works out how it should. You can't plan anything, right? You can try."