Is Pink Pregnant?!

Could Pink and hubby Carey Hart be expanding their family?

After a picture surfaced of the singer appearing to have a slight baby bump earlier this week, blogs began buzzing about whether Pink's pregnant.

So far, she’s not saying, but she Tweeted about the speculation. "Off to the gym," she wrote on Twitter Thursday. "Lord knows when this 600-lb baby comes out that I've been growing for 8 years, i better be strong and physically prepared!!!"

Pink and Hart, a motocross racer, wed in Costa Rica in 2006, only to split two years later, while Pink was working on her new album. They later reconciled.

The singer’s rep did not return calls for comment.