'American Idol" stars Kelly Clarkson and Justin Guarini laughed hysterically when I showed them last week's Star supermarket tabloid story "announcing" the couple's upcoming "$1 Million 'Gone With the Wind' [wedding] bash."

Chatting last week on the Miami Beach set of their upcoming "From Justin to Kelly'' big-screen debut, Clarkson was incredulous "that they can just make up all those details," including the "Gone With the Wind" theme and the alleged wedding reception location--the posh Mansion on Turtle Creek hotel in Dallas. "I've never even been there. ...We're just like sister and brother," said Clarkson, firmly denying she and Guarini "have ever, ever, ever" been more than "just the best of friends. ...and true soulmates."

Both singers-turned-actors do see one good aspect to the tabloid rumors--even if false. "It sure won't hurt when it comes to selling this movie," quipped Clarkson, proving she very quickly has come to understand the world of Hollywood marketing strategies.

* Guarini particularly loved the fact that the Star showed a photo of the couple supposedly smooching during a tryst on a boat. "It's a scene from the MOVIE!" blurted Guarini.

* Sources on the set of the film point out that a great deal of time has been spent to showcase Clarkson in the best light. "She's cute, but let's face it, she doesn't have a perfect body, or anything," said a production staffer. "When we shot a beach scene with everyone in swimsuits, it was very obvious that all the extras surrounding Kelly were a bit on the chunky side. ...They don't want to have the other girls showing her up.''