Actress Jennifer Grey is working on a secret dance movie, which many are speculating to be a potential sequel to the 1987 hit, "Dirty Dancing"."Dirty Dancing" featured Patrick Swayze as Grey's dance instructor and romantic interest, along with Jerry Orbach and Kelly Bishop as Grey's parents. The original film was set in 1963 at a Catskills resort.Jonathan Levine and Gillian Bohrer are driving the current untitled project, with a screenplay by Mikki Daughtry and Tobias Iaconis.Grey is collaborating with Lionsgate on the untitled dance movie in which she will star and executive produce, reports variety.com.The studio has refused to comment on whether the project, set in the 1990s, will bring back Grey's Frances "Baby" Houseman character.The original "Dirty Dancing" grossed $217 million worldwide and sold more than 1 million home video units. The song "(I've had) the time of my life" won an Academy Award for Best Original Song.A prequel "Dirty Dancing: Havana Nights" released in 2004.