AceShowbiz -

Jay Leno had a little experiment with Kim Kardashian's engagement ring during her appearance on "The Tonight Show with Jay Leno". The host tried to put an end to speculation that her 20.5 carat ring is fake, and he thought that the best way to prove it is to light it on fire.

Clad in a bright purple Zac Posen dress, Kim was a bit reluctant when Jay first proposed his idea. She even asked the 61-year-old stand-up comedian to sign a contract that he would pay the insurance if something happened to the jewelry, which is estimated at $2 million.

Jay convinced her that if the diamond was real, then nothing would happen. But if it was fake or it was just a cubic zirconia, it would catch the flame and get burnt, which meant Kris Humphries "has something to explain" to her.

The "Keeping Up with the Kardashians" star has since taken to Twitter to share the thrilling moment. "OMG u will NOT believe what Jay Leno did to my ring tonight on the show!!!! I almost cried! LOL," she tweeted soon after filming her appearance for the Tuesday night (June 14) episode.

The result of the test, however, is not included in a preview video for the talk show embedded below.