THIS summer, off-Broadway theatergoers are going to get a chance to see just how skinny Calista Flockhart really is.

The pencil-thin diva will star in ”A Gaggle of Saints,” three nasty one-acts by Neil Labute, who wrote and directed the acclaimed movie, ”In the Company of Men.”

”Gaggle” will run June 24 to July 24 at the Douglas Fairbanks Theatre on West 42nd Street, with Joe Mantello directing, theater sources confirmed yesterday.

Flockhart, on hiatus from ”Ally McBeal,” will appear in all three plays. In the first – ”Iphegenia in Orem” – she’ll sit mute while a young man tells her how he suffocated his baby daughter.

In the second – ”Medea Redux” – she’ll play a young woman who has an affair with her high school teacher and, years later, electrocutes him by tossing a radio into his bathtub.

The third play, ”Bash,” is about a group of Mormons who, while on a trip to New York, beat a homosexual to death. Flockhart will play the wife of one of the gay-bashing Mormons.

Rehearsals, which begin next week, promise to be grueling. So Flockhart, who’s been battling rumors of anorexia, had better beef up. Get thee to a Dairy Queen, Calista!

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The lineup for this year’s Tony Award broadcast, on June 6, is starting to take shape. And the big winner is ”Annie Get Your Gun,” which gets to kick off the Tony show with ”There’s No Business Like Show Business,” sung by its leads, Bernadette Peters and Tom Wopat.

”Annie” will also be the first Tony-nominated musical to perform a number on the telecast. That’s important, as every producer knows, since viewers drop off as Tony night drags on.

And so the show that goes on first reaches the biggest audience and generally gets the biggest pop at the box office.

”It Ain’t Nothin’ but the Blues” will be second, followed by numbers from ”Little Me,” ”The Civil War,” ”Fosse,” the shuttered flop ”Parade,” ”You’re a Good Man, Charlie Brown” and ”Peter Pan.”

Keith Sherman, a spokesman for the Tonys, declined to confirm the running order yesterday, saying it ”will not be locked into place for another 10 days.”

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The cast of ”The Iceman Cometh” is getting a raise. Their paychecks will triple for the last three weeks of the run, zooming from scale – $1,300 a week – to $3,500, producer Emanuel Azenberg said yesterday.

”It was a no-brainer,” he said. ”Everybody made a sacrifice going into this show, so if we’re going to make some money, some degree of socialism must be reinstated.”

”Iceman” will make at least $1 million profit, sources said.

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Broadway hoofer Belle Calaway will play Roxie Hart in the Broadway production of ”Chicago” for one week only, beginning May 25. Calaway has won raves on tour in the role … James Stovall, who starred in ”The Life,” is taking over the role of Coalhouse Walker in the Chicago production of ”Ragtime.” He replaces Hinton Battle, who had to leave the show due to a hip problem.