The `My Name Is Earl` actor and wife Ceren welcomed son Sonny into the world on June 16, his spokesperson has confirmed to People.
The little boy was born at 2.57am and weighed 7lb 6oz.
The happy news comes after the 41-year-old star - who has eight-year-old son Pilot Inspektor from a previous relationship with actress Beth Riesgraf and three-year-old daughter Casper with Ceren - renewed his wedding vows with his wife in November.
The couple - who have been married for over three years - tied the knot again in an intimate ceremony with their family and friends at Club Cicada in Los Angeles.
Despite the unusual choice of name for his eldest child, Jason has previously insisted Pilot doesn`t resent him for it.
He said: "Pilot loves his name. He goes to a little hippy school where all the children have interesting names. He has a friend named Zoot. Then there`s Cosmo, and lots of others too!"