The couple, who wed in June 2002, are also parents to son Jordan Ezra, born in October 2002, and daughter Penelope, born April 19, 2005.
When Jordan was only a year old, his father, now 23, told PEOPLE, "Having a baby is a life-changer. It gives you a whole other perspective on why you wake up every day."
Hanson, which includes Taylor's older brother Isaac and younger brother Zac, rose to fame in the summer of 1997 with their hit single "MMMBop." According to the band's Web site, they are now are wrapping up their fourth studio album, set to bow early next year.