The 'Because Of You' hitmaker and her new husband are spending all their spare time in bed to get pregnant as soon as possible.
Rabbits have an extraordinarily high sex drive, something the 31-year-old singer says she can identify with as she is so desperate to have a child.
Speaking on The Tonight Show With Jay Leno on Monday, Kelly said: "We want a baby now! Practice makes perfect! We're trying, trying, trying ... Like rabbits!"
The former American Idol winner says becoming a step-mother to Brandon's children from a previous relationship - Savannah, 11, and Seth, seven - has made her want more maternal than ever.
She said: "We have two kids. And they're so great. And I never wanted kids before, but now I want, like, five."
However, Kelly fuelled rumours she might already be expecting her first child when she refused to give a direct answer to Jay's questions.
The host probed, "Are you pregnant now?" prompting Clarkson to ask, "What are you saying?"
Referencing his chat show rival Elle DeGeneres, Jay insisted: "I always get these stars who come on and go, 'I'm thinking about having a baby,' and then the next week they go on Ellen and announce it there. So I'm asking you, 'Are you pregnant? Remember - you're under oath!' "
Kelly - who wed music manager Brandon in Tennessee last month - coyly replied: "We are not announcing anything right now!”