The Tea Party Express played a key role in some of the most surprising GOP primary wins in 2012 -- showering early support on Sharron Angle, Christine O'Donnell and Joe Miller.
[TPM SLIDESHOW: Tea Partiers Storm DC For Second (And Smaller) 9/12 Rally]
CNN's political director Sam Feist said in a statement that the event will showcase the "diverse perspectives" within the Republican Party, calling the tea party movement a "fascinating, diverse, grassroots force."
Should be quite a show.
Correction: Mark Williams was a frequent guest on CNN but not a CNN "contributor" as this post originally stated. We regret the error.