Julia Stiles says Jennifer Lopez was ''very, very disciplined'' on the set of 'Hustlers'.

The 'Save The Last Dance' actress plays the part of a journalist who closes in on Jennifer's alter ego Ramona and her stripper pals - who are played by the likes of Cardi B and Constance Wu - who carry out a series of crimes to seek revenge on their Wall Street clients.

And the 38-year-old star has revealed how her co-star was extremely professional in rehearsals.

Speaking to InStyle magazine, Julia said: ''She's very, very disciplined.

''[Jennifer] was handed a full page monologue my first day shooting with her and she just read it a few times, closed her eyes, and then opened them and was like, OK, let's go.'''

The '10 Things I Hate About You' star also discussed how female characters who have behaved immorally always get judged ''a lot more harshly'' than men do.

She explained: ''We judge female characters a lot more harshly, and if you have a female character doing something questionable, immoral, illegal, or unlikable, I find that storytellers have to jump through hoops to explain why she did that.

''If a male character's running around with a gun, it's cool, but if a woman is doing it, we have to have seen her suffer some horrible tragedy in order to justify it.''

Meanwhile, whilst Jennifer, 50, might be a pro on screen, she previously admitted she was scared of taking on the stripper role because she is ''exposing'' herself more ''emotionally and physically'' than ever before.

She said: ''It's a nightmare thinking about being up there.

''I'm exposing myself let's say - emotionally and physically more than I've ever done in a movie.

''And I've done love scenes and this and that, whatever, but not like I was up there like that.''