here's what we know...

The two-hour extravaganza begins tonight at 8 p.m.

All of the former Idols, excepting Fantasia who's on Broadway, will be there to perform. Green Day will be there. Gladys Knight will sing with the women; Smokey Robinson will sing with the guys.

Only the top three get duets, and Melinda's will be with BeBe and CeCe Winans. Beatboxer extraordinaire Doug E Fresh is in negotiations to will appear. Rumor has a Dreamgirls performance associated with Jordin's name, but that is squirrelly.

And yes, they're gonna milk the Sanjaya phenomenon, giving him, reportedly, a duet (and a short platinum hairstyle) with Journey lead singer Steve Perry. (You know how we love Journey. Randy worked with them, you know.) Aerosmith's Joe Perry. You Really Got Me with that one.

If there are more credible spoilers, here's where they will be.