Their representative says the pop and rock star couple have named their son Bronx Mowgli. The baby, born Thursday night, weighed 7 pounds, 11 ounces.
Bronx is the first child for Simpson-Wentz, best known for the hit "Pieces of Me," and Wentz, bassist for the platinum rock band Fall Out Boy. They were married earlier this year.
Their representative said in a statement: "Ashlee, Pete and baby Bronx are all healthy and happy, and thank everyone for their well wishes!"