Zac Hanson Expecting a Baby With Wife Kate

Zac Hanson's wife Kate is pregnant with the couple's third baby, due this fall. Dave M. Benett/Getty Images

The Hanson brood just keeps getting bigger! Youngest brother Zac Hanson — who was just 11 years old when he and siblings Isaac and Taylor became a major pop sensation with the song "MMMBop" — is set to welcome his third child with wife Kate this fall, he confirms to Us Weekly.

"We are so happy and thankful to add more life and love to our family!" the singer, now 27, tells Us. (He and Kate, married since 2006, are also parents to son Shepherd, 5, and daughter Junia Rosa Ruth, 2.)

"It's fun this time to watch the little ones so excitedly anticipating their new sibling," he adds.

The new little bundle of joy will be in good company, not just with his or her own brother and sister but also with Zac's nieces and nephews. Older brother Isaac, 32, has two kids, 6-year-old Everett and 4-year-old Monroe, with wife Nicole. And Taylor, 30, welcomed his fifth child, Wilhelmina Jane, with wife Natalie last October. She joined big siblings Ezra, 10, Penelope, 8, River, 6, and Viggo, 4.

The Hanson brothers are also adding to their musical arsenal this year. Anthem — the band's 11th album — is scheduled for release on June 18.

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