Here's "American Idol" standout Siobhan Magnus on Tuesday night's show (left) -- and Debra Messing as Grace Adler in a flashback episode of "Will & Grace" (right).
One of them brought out the Lambert cackle to sing "Paint it Black" in an '80s prom dress on Tuesday.
We're just sayin'.
'Idol' Chick -- Amazing 'Grace'
3/18/2010 2:03 AM PDT BY TMZ STAFF
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