We know Kelly Clarkson can sing. That’s why she won the first-ever season of 'American Idol' and why her new album 'Stronger' is one of our fave platters of the year. But the 'Mr. Know It All' singer also has a wicked sense of humor, which she let rip during the taping of her VH1 'Unplugged' special, which is set to air on Friday, Nov. 18 at 11PM. Make sure you tune in in two days.

Billboard corralled some of the choice quotes that Clarkson delivered during the taping which didn't make it into the broadcast version … For obvious reasons! Kel can get quite raunchy.

When her boobs tumbled out of her dress during one point of the set, Clarkson quipped: "Was it Erin Brockovich the whole time?! It's funny because I have no boobs but they're coming out." She addressed her lack of well-endowed-ness, saying, "I realize God didn't give me boobs cuz if I had them, I'd show them off. I'd be a slut."

When she messed up the lyrics of a song but kept going, she acknowledged that "I should have just stopped -- just like most of my relationships!" Zing.

She also joked about donning two pairs of Spanx, the undergarments that most celebs won't step onto a red carpet without wearing, since they hold everything in, saying, "Oh dear God, can we just sing?!"

We love that Clarkson has such a killer and self-deprecating sense of humor.

Her five-song set consisted of the following cuts: 'I Know You Won't, which is a Carrie Underwood cover; 'Darkside'; 'What Doesn't Kill You (Stronger)'; 'Mr. Know It All'; and 'Since U Been Gone.'