Fall Out Boy's Pete Wentz and girlfriend Meagan Camper welcome baby girl

PHOTO: Pete Wentz of Fall Out Boy checks in during "The Late Late Show with James Corden," Jan. 31, 2018.PlayTerence Patrick/CBS via Getty Images
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Congratulations are in order for Fall Out Boy bassist Pete Wentz and his girlfriend, Meagan Camper, who welcomed a baby girl over the weekend.

The musician announced the news via Instagram on Mother's Day.

"So excited to introduce Marvel Jane Wentz," Wentz, 38, wrote in a caption. "Feeling so grateful that she’s here... annnnd she’s already ready to takeover the world. Happy Mother’s Day @meagancamper and all the moms out there. We [heart] you."

Baby Marvel is the second child for the couple, who are also parents to a boy, Saint Lazlo, born in August 2014.

Wentz also shares a 9-year-old son, Bronx Mowgli, with his ex-wife, Ashlee Simpson.

PHOTO: Musician Pete Wentz and model Meagan Camper attend the 2017 Pre-GRAMMY Gala And Salute to Industry Icons Honoring Debra Lee at The Beverly Hilton Hotel on Feb. 11, 2017 in Beverly Hills. Jeff Kravitz/FilmMagic/Getty Images
Musician Pete Wentz and model Meagan Camper attend the 2017 Pre-GRAMMY Gala And Salute to Industry Icons Honoring Debra Lee at The Beverly Hilton Hotel on Feb. 11, 2017 in Beverly Hills.

The bassist will have a few months to spend at home with his new baby until Fall Out Boy embarks on a 2018 tour in late August to promote the band's seventh studio album, "MANIA."