Of course, the two American cool kids gave their little girl a unique name: Gravity Blue Smith.
18-year-old Lucky took to Instagram to announce her arrival with a gorgeous photo, captioned: "She's here😍😍😍 meet Gravity Blue Smith, I've never felt so happy... I love you more than anything in this whole world little princess."
26-year-old Stormi shared another black and white photo a few minutes later, featuring new mum, dad and baby.
"Welcome to the world little angel, the most perfect beautiful gift I could have ever dreamed of little miss Gravity Blue Smith."
Congrats to the happy couple!
This article previously appeared on marie claire.