Here's another terrific reason Kelly Clarkson ditched a big wedding ceremony in favor of eloping with fiancé Brandon Blackstock: She's planning for a baby!

The 'Tie It Up' singer isn't wasting any time on expanding her family, even though she did recently have to deny that a pregnancy was the reason she changed her mind about having a big wedding affair. (In fact, it was Clarkson's upcoming Christmas album and a need for more privacy that prompted the couple to make the switch.)

The singer is already a stepmother to Blackstock's two kids, aged 12 and 6 respectively -- something she loves. She gushes, "We all live together and everything … it’s so different, but it’s perfect."

Almost perfect, actually. While Clarkson says she lucked out because Blackstock's two children are so awesome, she still wants to add to the brood, and it's her stepkids-to-be who are beyond onboard with that plan.

"Savannah, the 12-year-old, is like, ‘I want a little sister,'" the star reveals. "She’s so excited.”

Like a dutiful stepmom and mother-to-be, Clarkson has already started strategizing and planning for pregnancy. "It’s all about just making my body the most healthy inside out. And I’m reading all these books," she confesses.

It'll be baby-on-board sooner rather than later for Clarkson and her man.