Ashlee Simpson-Wentz and her rocker hubby Pete Wentz welcomed son Bronx Mowgli Wentz, their first child together, Thursday at Cedars-Sinai Medical Center in Los Angeles.
The baby boy weighed in at 7 pounds, 11 ounces and measured 20 1/2 inches.
"Ashlee, Pete and baby Bronx are all healthy and happy, and thank everyone for their well wishes," a rep for the couple told People.
The birth comes almost three weeks after the 29-year-old Fall Out Boy mastermind told Ryan Seacrest that his 24-year-old missus was "very pregnant…She's at the very end, and it could happen at any point."
During an Ellen DeGeneres Show taping on Monday, new aunt Jessica Simpson, said her sister was considering inducing labor. "I think she's really just jumping around trying everything right now" to get the baby out.
As for the tot's name, Wentz told Seacrest that they were not looking to go down in the annals of punch line-ready celebrity monikers.
"I want to meet the baby first. 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."
In preparation for the big day, Simpson-Wentz, along with Jessica, mom Tina and famous friends Nicole Richie and Emmy Rossum, held a Winnie-the-Pooh baby shower at the Hotel Bel Air three weeks ago.
The new mom kept a mostly low profile during her lengthy pregnancy, but did express her excitement at the prospect of entering motherhood in a post to her MySpace blog over the summer.
"Carrying a child is the most inspiring, emotional, amazing experience of my life…I am only concerned with having a healthy pregnancy and a healthy baby."