A CRITICAL MASS

If Paramount didn’t pre-screen “Back to the Beach” for critics, how come its opening-weekend movie ads were already carrying an enthusiastic quote from the Chicago Trib’s Gene Siskel?

“It’s the best piece of musical comedy nostalgia since ‘Grease,’ ” blurbed Siskel, concurring with the energetic TV thumbs-up that he and “Siskel & Ebert & the Movies” cohort Roger Ebert gave it.

But that line never appears in the equally praise-mongering newspaper review that Siskel wrote Aug. 7, the same day that “Beach” opened. Where did the quote come from?

According to Paramount, it was pulled from an Aug. 2 feature article by Siskel about Frankie Avalon and Annette Funicello’s big comeback. In order to prepare for his interview with Frankie and Annette, a studio spokeswoman said, Siskel flew to Cleveland for an “interview screening” of “Back to the Beach.”

Siskel couldn’t be reached for his clarification. The person who picked up his phone at the Tribune said, “We don’t see him around here too much these days.”