Singer Kelly Clarkson was so unprepared for a proposal from her boyfriend Brandon Blackstock in December (12), she was wearing a sweatshirt and Ugg boots when he asked her to marry him.

Reba MCEntire's stepson popped the question to Clarkson at their Nashville, Tennessee home over the Christmas holidays and the Stronger hitmaker admits she wasn't really dressed for the occasion.

She tells People magazine, "We always play darts and drink beer and listen to vinyl. That's our thing, but out of nowhere I just said, 'Thanks for being an awesome guy. I've never been properly loved by a man,' and I was just like, 'I thank you so much for that'. Then, all of a sudden, he leans in and kisses me and he's on his knee.

"Still at this point I'm like, 'Did he drop something?' Not a damn clue! If I did I would have worn something besides Uggs and a sweatshirt with no bra."

After Blackstock proposed with a canary yellow sparkler, the singer was so shocked she forgot to say yes.

She jokes, "I was like, 'Are you gonna put the ring on?' And he looked up and was like, 'Well, usually at some point the girl says yes or no.' And I'm like, 'Oh, obviously yes!'"