But the theme was actually intended to honor another television pioneer: Soul Train creator Don Cornelius, who also passed away this year.
Ryan Seacrest recognized his hero, saying Idol wouldn't exist with Clark, who died of a massive heart attack Wednesday. But, he acknowledged, the show must go on: "The theme is based around a show similar to American Bandstand," he said, "Soul Train."
So how did the top seven contestants do? Keep reading for a full recap of Wednesday's show ...
After last week's surprising results, when once-favored performers Jessica Sanchez, Joshua Ledet and Elise Testone found themselves in the bottom three, it was anyone's game.
Hollie Cavanagh kept her momentum going after last week, earning raves for her soulful take on Adele's "Rolling in the Deep" and Dusty Springfield's "Son of a Preacher Man."
Colton Dixon earned props for his hair-metal rendition of Lady Gaga's "Bad Romance," but not so much for his bizarre power-ballad spin on Earth Wind and Fire's soul-disco classic "September." (His wardrobe – super-tight red leather pants and a black drape coat – was also ill-advised.)
Meanwhile, Phillip Phillips, who has yet to land in the bottom three, and Skylar Laine continue to improve week after week. "You and Phillip have no problem connecting," said Randy.
Phillips scored with an inventive take on Usher's "You Got It Bad," which got Lopez so overheated, she declared afterwards, "You are so sexy!"
And Laine nailed the country rendition of Gaga's "Born This Way." "You've given all the other girls a run for their money," said Steven Tyler.
Joshua Ledet may have fared the best of all performers – particularly according to the judges, who jumped to their feet for standing ovations after each performance. "I still want more at the end!" said Lopez. "Please America, don't send this boy home!"
Perhaps Lopez should have asked for similar mercy for Jessica Sanchez. After getting saved last week, Sanchez seemed to lose her confidence but delivered with both performances, including Otis Redding's "Try a Little Tenderness."
Said Lopez, perhaps a little nervous for the former frontrunner, "We gotta really start pushing your performances."
Michael Becker / FOX (2)