Salma Hayek discusses working with Angelina Jolie's sons on film project

Salma Hayek has opened up about working with Angelina Jolie and her two sons on a new film.

The 58-year-old Mexican acting icon plays Nina in Without Blood - a film written and directed by Oscar-winning actress Jolie, 49.

And it seems it was something of a family affair on set as Jolie hired her sons Maddox, 23, and Pax, 20, to work on the project as assistant directors.

Having her friend's children on set proved a difficult adjustment for Hayek, who told People, "It is kind of funny. I was teasing them at the beginning, but then I had to say, 'No. I have to separate and just treat them like professionals because it's disrespectful'."

She also noted that their mother did not go easy on them, revealing, "She's demanding... They got the respect of the crew, and they were good with the crew, and they were very in their place. They were not treating me like they treat me outside of there. They were very, 'You have to come,' and I go, 'OK!' It was kind of fun."

She also discussed working with Jolie as a director, saying, "I was surprised, even though we are very close and stuff, but I was (surprised by) how warm and generous and kind she was as a director to the actors. It was really something.

"I've worked with great directors that are really focused, but maybe because she's also an actress ... everything that maybe she wished somebody would've done for her, she did for us."