Reps. Mary Bono Mack (R-Calif.) and Connie Mack IV (R-Fla.) are welcoming their first grandson, Sonny William Hrabe.

The 8-pound, 6-ounce bundle was born Thursday to Bono Mack’s daughter, Chianna Maria Bono, 21, and her husband, local boy (Falls Church High School class of 1978) Mark Hrabe, at 3:12 p.m. — roughly five hours after Bono Mack leaked that she and Mack were already hunkered down in the delivery room awaiting the arrival.

“We are so delighted and thrilled with the birth of our first grandson, Sonny William Hrabe. Both mom and baby are healthy and doing very well, and Chianna is overjoyed about becoming a mother,” Bono Mack gushed in a release.

Bono Mack’s stepson, Chaz Bono, was equally exuberant, sharing his well wishes with the entire Twitterverse.

“Happy to share that my nephew, Sonny William Hrabe, was born today, on his granddad’s b day. Congrats to all the Bono’s, Mack’s, & Hrabe’s,” Chaz Bono tweeted.

Baby Sonny shares a birthday with his father, who just turned 52, and, as Chaz Bono noted, with his late grandfather, Rep. Sonny Bono (R-Calif.), who would have been 77 this year.

No word on when the burgeoning Hrabe clan is expected to the leave the hospital and return to their home just across the river in Dumfries, Va.