Whitney Houston's Final Movie Coming Real Soon?

Sources connected to the production tell us ... the people working on "Sparkle" -- starring Whitney and Jordin Sparks -- are working "around the clock" to finish post-production work on the movie as quickly as possible.

We're told the building where the film is being edited is also under tight watch -- with ramped up security in the hopes of preemptively clogging a leak.

According to various reports, Sony was hoping to release the movie in August.