There is some kindness – once the singing stops. Cowell even acts as wise older brother, says Abdul. "When I start dating someone he tells me, 'I'm going to give you some advice: Try not to talk too much,' " she laughs. But when she broke up last year with former Smith & Wesson executive Colton Melby, "Simon was very much there for me."

So yes, concludes Cowell, "it is a strange relationship, to say the least. But I couldn't imagine now doing the show with anybody else." Says Abdul: "We do get along . . . as long as he's on his side and I'm on mine."

• Written by Tom Gliatto, Mike Lipton and Jill Smolowe. Reported by Darla Atlas, Andrea Billups, Todd Gold, Wendy Grossman, Lisa Ingrassia, Shia Kapos, Susan Mandel, Rebecca Paley, Monica Rizzo and Sandra Sobrieraj Westfall