Pop star Pink is pregnant with her second child.

The Just Like Fire singer and her husband, motocross star Carey Hart, are expecting a sibling for their five-year-old daughter Willow Sage.

Pink announced the news to fans in an Instagram post on Saturday (12Nov16), sharing a photo of herself sporting a big baby bump as little Willow cuddles up to her mom.

"Surprise!," she simply captioned the image.

The 37-year-old, who has been out of the spotlight for the last few months, has frequently gushed about her life as a mother, insisting having a "successful family" was her "absolute number one goal in life".

"I love being a mama," Pink told breakfast show Good Morning America in May (16).

The star went on to reveal she would love to expand her family, but joked, "I wanna say that Carey Hart's an awesome husband and a really good dad, but he's also like a second child!"

Earlier this year (16), Pink admitted she and Carey found it hard to make time for one another, as he often struggles to stay awake for them to get intimate.

"He always falls to sleep putting Willow to bed," Pink shared on The Ellen DeGeneres Show. "The other night I said, 'Are you going to stay up tonight?' And he said, 'I would like to.' I said, 'I don't really know what that means. Should I light candles and open wine and put on a show? Like, are we going big here? Or are you going to fall asleep again?'"

Carey, 41, ended up falling asleep, but Pink couldn't help but forgive him: "He's an incredible dad," she said. "That's why he falls asleep, because (Willow) wants him to stay."

The couple will celebrate its 11th wedding anniversary in January (17), but the stars' relationship hasn't been without problems in the past. Pink and Carey briefly separated in 2008, before rekindling their romance and welcoming Willow in 2011.