Mum-to-be Kelly Clarkson has slammed outrageous rumours her new husband Brandon Blackstock is involved in an extramarital affair and expecting a child with another woman.

The Since U Been Gone hitmaker recently became the subject of tabloid fodder when a woman came forward claiming she was having an affair with Blackstock and was five months pregnant with his child.

However Clarkson finally spoke out against the rumours on Friday (06Dec13), taking to Twitter.com to deny the allegations.

She writes, "Keep hearing random rumors of me & Brandon splitting or that's he's cheating on me. Stop with all the lying please.

"False rumors don't bother me & Brandon but they do affect the lives of our (sic) 12 & 7 yr old.They're kids & don't get that people can print lies."

Blackstock's two children are from a previous relationship. He wed Clarkson in October (13) and just weeks after tying the knot, the singer announced she is pregnant with her first child.