Singer Kelly Clarkson is one step closer to becoming Mrs. Brandon Blackstock after obtaining a marriage licence in Tennessee.

The couple filed for the legal document in Sumner County, near Nashville on Tuesday (15Oct13), giving Clarkson and Blackstock 30 days to wed.

The Since U Been Gone hitmaker recently revealed they were planning to marry in a small ceremony by the end of October (13), after previously contemplating a massive celebration.

She told, "We had a wedding planned, like a huge one - and we still have a wedding planned, but we're not doing the big huge one.

"We're just gonna (sic) go off with the kids and go get married and it's just gonna be literally, seriously small."

Blackstock proposed to Clarkson last December (12).

It will be the singer's first union, while Blackstock has two children from a previous marriage.