That Aug. 27 matinee performance at the Ambassador Theatre also makes the acclaimed production the longest-running American musical in Broadway history, since the top three productions (The Phantom of the Opera, Cats and Les Miserables) are all British imports.

"What a momentus occasion this is!" said producer Barry Weissler in a statement. "Of course we're thrilled to take the number four position in the list of long-runners, but to also celebrate the fact that Chicago is now the longest-running American musical in Broadway history makes it all the more spectacular. And just as Velma Kelly sings, we couldn't have done it alone. This milestone would never have happened without the amazing group of people who've lent their talents and expertise to our production over the past 15 years -- the phenomenal cast, crew, production team, stage managers, advertising and marketing executives, business managers, casting directors, ushers, musicians, dance captains...and the list goes on. And of course, our incredible and enthusiastic audiences. Over five million people have seen Chicago on Broadway to-date, and they just keep coming. It's truly a phenomenon worth celebrating."

As of Aug. 27, the top-five longest-running productions of all time are as follows:

1. The Phantom of the Opera (9,810)
2. Cats (7,485)
3. Les Miserables (6,680)
4. Chicago (6,138)
5. A Chorus Line (6,137)

The Broadway production currently stars two-time Tony Award nominee Charlotte d'Amboise as Roxie Hart, Nikka Graff Lanzarone as Velma Kelly, two-time Tony Award nominee Christopher Sieber as Billy Flynn, Chris Sullivan as Amos Hart and Carol Woods as Matron "Mama" Morton. As previously announced, former "American Idol" judge Kara DioGuardi will make her Broadway debut as Roxie Hart in an eight-week engagement beginning Sept. 5. DioGuardi will be joined by longtime Chicago veteran Amra-Faye Wright as Velma Kelly. (Nikka Graff Lanzarone plays her final performance Sept. 4.)

The revival of Chicago began life as one of the three annual Encores! presentations offered by City Center. The musical opened on Broadway at the Richard Rodgers Theatre in Nov. 1996 where it remained through Feb. 1997. The musical transferred to the Shubert Theatre on Feb. 11, 1997, and played that house through Jan. 26, 2003. The revival reopened at the Ambassador Theatre, its current home, on Jan. 29, 2003.

Chicago won the Tony Award for Best Revival of a Musical in 1997 as well as awards for actors Bebe Neuwirth and James Naughton, director Walter Bobbie, lighting designer Ken Billington and choreographer Ann Reinking. The original production was directed and choreographed by the late Bob Fosse.

The Ambassador Theatre is located at 219 West 49th Street.

Visit www.ChicagoTheMusical.com for more information.