Production on the Michael Bay-produced 'Teenage Mutant Ninja Turtles' is heating up in NYC, as seen through the countless paparazzi pics of Megan Fox and the pre-CGI turtles swarming out from the set. And more keep coming by the day, but the latest batch revealed one big-haired surprise for us -- THE Whoopi Goldberg.

Photographers got a shot of famed comedienne Whoopi Goldberg on the set of 'TMNT' today sporting a voluminous afro. It's not known what exactly she was filming, but based on the photo (shown below) it looks like she's got some scrubs underneath that large coat of hers. Take a look...

...But who could she be playing? Already known to us are Megan Fox as April O'Neil, Will Arnett, the Ninja Turtles -- Alan Ritchson as Raphael, Pete Ploszek as Leonardo, Jeremy Howard as Donatello and Noel Fisher as Michelangelo -- William Fichtner rumored to be Shredder and Danny Woodburn as Splinter. So who's left?

Perhaps Goldberg will have some sort of surprise cameo, and if so, sorry for spoiling the surprise! We'll keep you updated as more information develops.