Natalie Portman and Mila Kunis say Black Swan director Darren Aronofsky tried to stoke a feud between them while on set in order to mimic their on-screen rivalry.

Natalie Portman and Mila Kunis reflect on how Darren Aronofsky tried and failed to push a rivalry between the two stars on the set of 'Black Swan'

Darren Aronofsky recalled unsuccessfully trying to start a feud between Natalie Portman and Mila Kunis to ramp up the onscreen tension in 'Black Swan': 'They're both very clever and were instantly privy.