US singer Pink has announced the news that she is pregnant with her second child.

The 37-year-old Grammy winner took to social media on Saturday to share that she is expecting her second child with husband Carey Hart.

"Surprise!" she wrote alongside a photo with the couple's five-year-old daughter, Willow Sage. The mother-daughter duo wore coordinating off-white ensembles and brown hats, and Willow's head was resting on her mom’s growing baby bump.

The Pennsylvanian musician and her motocross-champ husband welcomed Willow back in June 2011. And judging by the size of the baby bump, it won't be long before she has a first brother or sister.

In a previous interview with People, Pink spoke about motherhood. "I have lived a lot of life in a very short time, and you get hardened a little bit - you get jaded, you build up walls," she said.

"And when you see this little kid, and you get to watch them through infancy to toddler to little person, it’s amazing."