This is the first child for P!nk and her husband, motocross star Carey Hart.
The 31-year-old singer said she gave birth Thursday.
"We are ecstatic to welcome our new beautiful healthy happy baby girl, Willow Sage Hart," People.com quoted P!nk as writing. "She's gorgeous, just like her daddy."
Wisconsin business offering 'therapeutic cuddling' forced to close
Exploding whale video goes viral on Internet