The musician and new dad shared an adorable photo of his 5-week-old baby boy Nash Dylan to Twitter on Thursday, showing the little guy wearing a shirt featuring the cover of the superstar pop group‘s 1998 self-titled debut album.
“I think JC is his favorite,” joked Kirkpatrick, 46, in the accompanying text, referring to his former ‘NSYNC bandmate JC Chasez.
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There are likely no hard feelings where Kirkpatrick is concerned. The guys are still tight, attending weddings together (in fact, all five members were on hand when Kirkpatrick tied the knot with wife Karly in 2013) and even reuniting in August 2016 to celebrate Chasez’s 40th birthday.
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“Karly and I are over the moon excited that we are welcoming a new addition to the family,” Kirkpatrick told PEOPLE exclusively after announcing the couple were expecting. “We are both looking forward to becoming parents, and learning how much fun having a child will be.”