They're real and they're fabulous.

That's the message Kim Kardashian wants to get off her, well, chest during a Thursday appearance on Piers Morgan Tonight with older sis Kourtney, 31.

"There's a lot of plastic surgery rumors that swirl and I'm the first one to be super honest," says the Kourtney and Kim Take New York star, 30, who admits to trying Botox. "And so everyone was talking about that, saying that they must be, you know, fake."

The truth? "They are real," says Kim, in the video above. "They are completely 100 percent real."

And when host Piers Morgan tells the reality star, "You just look like you must have had [surgery]," she responds, "That's what Spanx and masking tape are for."

However the eldest Kardashian -- and mom to son Mason, 13 months -- had a more permanent solution for her bust.

"These babies are not real," she laughs while pointing at a cardboard cutout of herself. "I used to make fun of [Kim] when we were little and then I went and got surgery."