The baby boy, weighing in at 7 pounds, 11 ounces and measuring 20½ inches, was born at Cedars-Sinai Medical Center in Los Angeles.
"Proud new parents Pete Wentz and Ashlee Simpson-Wentz welcomed new son, Bronx Mowgli Wentz, late this evening," a rep for Ashlee told E! News. "Ashlee, Pete and baby Bronx are all healthy and happy, and thank everyone for their well wishes!"
So what's with the name? Ironically, Wentz told Ryan Seacrest in a recent interview that the couple wasn't planning anything weird. "I want to meet the baby first," Wentz said. "My friend said it - you've gotta have a baby with a name that could be a rock star or a senator, so he'll get work either way."
While Ashlee kept a low profile during most of her pregnancy, she did blog about it on her MySpace page over the summer.
"Carrying a child is the most inspiring, emotional, amazing experience of my life..." she wrote. "I am only concerned with having a healthy pregnancy and a healthy baby."
Simpson and Wentz married in May after news of the pregnancy leaked to the press.
November 21, 2008
The SheKnows interview with Ashlee Simpson
The SheKnows interview with Jessica Simpson
The story of Ashlee and Pete's wedding