UPDATE, April 11:
For Americans worried about what fast food restaurants are doing to their buns, KFC has a solution -- eliminate them.
Those would be sandwich buns, which you won't find on the chain's new Double Down. Instead, you'll find two slabs of fried chicken holding together two pieces of bacon, two melted slices of Monterey Jack and pepper jack cheese and Colonel's Sauce. Evidently, no vegetables were harmed in the making of this sandwich.
On the off chance you're feeling health conscious while ordering, you can opt for grilled chicken instead of the original recipe.
As reported by the Huffington Post last August, the sandwich was initially made available in two test markets -- Rhode Island and Nebraska. KFC's Double Down gamble paid off, and they're rolling out the creation nationwide starting on April 12. Their decision was first announced on April 1, leading some to believe it was an April Fools' joke. Turns out, the only gag involved was the reaction of vegans.
If you're itchin' for this chicken, there's a countdown clock on KFC's website, along with some surprising nutritional news. The grilled version has "only" 460 calories and 23 grams of fat, while the original recipe version has 540 calories and 32 grams of fat. That's nowhere near some early speculation in the Vancouver Sun that one sandwich might set you back 1228 calories. Still, it might be wise to run a few extra laps before crossing the road for this chicken.
In a press release about their latest culinary achievement, KFC posed the "obvious" question: what happens to all the buns? Surely that was the first thing that crossed consumers' minds when they saw the Double Down. To satisfy your hunger for information, the chain says they will donate the "unneeded" bread, giving "both buns and funds to food banks across the country." Ordering this sandwich could actually be good for somebody besides your local cardiologist.
It remains to be seen if Jim Gaffigan will incorporate the Double Down into a stand-up routine (see: Bacon, Hot Pockets, Cinnabon and Waffle House). [As funcrusherplus points out in the comments, Patton Oswalt might have some fun with this -- video contains NSFW expletives.]