This so-called raunchy, R-rated version of Grease includes songs few have heard before, with a special framing device devised for this revival (it features a class reunion of older actors 50 years after the action of the Chicago-set musical). The production opened May 2.

The Original Grease is written by Jim Jacobs and Warren Casey and directed by ATC artistic director PJ Paparelli with musical direction by Roberta Duchak and choreography by Jim Corti.

On May 21, ATC hosted nearly 300 Alumni of Taft High School's Class of 1960 during two special alumni performances of The Original Grease. Many of the actual "Pink Ladies" and "Greasers" that the characters in the play are based on were in attendance, according to ATC.

In preparation for the alumni performances, Jacobs and Paparelli "introduced a new opening and closing sequence into the production in addition to revised material and changes."

"The Original Grease's reception in Chicago has been overwhelming," Paparelli said in a statement. "The feedback Jim and I have received has been extremely helpful in refining this new version. We wanted to introduce a more Chicago-centric opening and closing of the show for Jim's graduating class in addition to other changes that we couldn't make in preparation for opening the show. With a tighter running time and a more heartfelt and Chicago-based bookend for the show, we look forward to sharing the new material with audiences." The revised production began performances on May 21. The revised production now runs 2 hours and 12 minutes, plus a 15 minute intermission.

Read Playbill.com's recent feature about this "new-old" Grease.

ACT added 7 PM Sunday evening performances beginning May 15 and is now extended through Aug. 21 at ATC's home at 1909 W. Byron St.

For tickets and information, visit www.atcweb.org or call (773) 409-4125.