The youngest Hanson brother booked a new gig last week as MMMPops after the birth of his baby boy on May 27.
Zac Hanson, 22, and his wife, Kate, 24, became the parents of John Ira Shepherd Hanson after the birth at a Tulsa hospital, The Associated Press reported.
The baby boy weighed 8 pounds, 4 ounces, according to the AP " exactly the weight Zac's dreamily disheveled hair had in the late Nineties.
Zac and his brothers, Taylor, 25, and Isaac, 27, make up the well-known Okie rock band Hanson, perhaps best known for the 1997 album "Middle of Nowhere." The album sold more than 10 million copies worldwide thanks largely to the annoyingly infectious song "MMMBop."
Taylor is already father to three children, and Isaac is father to one and is expecting another next month, according to the band's Web site.
Zac told People readers in November that "watching" the Hanson kids is "going to inspire a lot of music," though early rumors of a Hanson family supergroup haven't been confirmed.