May 14 (UPI) -- Fall Out Boy bassist Pete Wentz has welcomed his second child with longtime girlfriend Meagan Camper, a baby girl named Marvel Jane Wentz.
"So excited to introduce Marvel Jane Wentz. Feeling so grateful that she's here... annnnd she's already ready to takeover the world," the rockstar said on Instagram Sunday next to a photo of himself laying in the hospital bed next to Camper and the newborn alongside their 3-year-old son Saint Laszlo and 9-year-old Bronx Mowgli, whom Wentz shares with ex-wife Ashlee Simpson.
"Happy Mother's Day @meagancamper and all the moms out there. We [heart emoji] you," he continued.
Wentz, 38, and Camper, 29, began dating in 2011 following Wentz's divorce from Simpson. The couple announced that they were expecting on New Year's Day.
"We have a lot of testosterone in our house," Wentz said previously to People magazine. "I see my friends who have daughters, and it seems like a whole different kind of love that they have for each other, so I look forward to that being a completely new journey. Hopefully it'll bring some balance to our home!"