Riz Ahmed has said he was impressed by how quickly Kate Hudson could get into character in The Reluctant Fundamentalist.
The pair star as lovers Changez and Erica in Mira Nair's big-screen adaptation of Mohsin Hamid's best-selling novel, and the British actor recalled how the Hollywood actress could switch from being a mum to her alter-ego in seconds.
"She's a fantastic actress. I'll tell you the truth - she was breastfeeding and had just had a baby so she had a two-month-old on set," he said.
"Literally, she would be breastfeeding and then they would call 'rolling'. She would quickly hand the baby over, they call 'action' and she would burst into tears. I was blown away by that sort of focus so it was impressive."
Riz joked the newborn didn't put a damper on the raunchy scenes, adding: "The child was not on set during the sex scenes. I'm not an animal!"
The film follows young Pakistani Changez as he becomes more disillusioned with life in the US, when perceptions towards Asians changed after 9/11, but the 30-year-old said he hadn't been the subject of prejudice.
He said: "I feel like I could really relate to this character because he goes up between classes and cultures."
Having worked with the likes of Kate and rapper Plan B (Ben Drew), Riz has his eye on collaborations with other stars, saying: "There are loads of people I would love to work with. Some of my favourite actors are James McAvoy, Andrea Riseborough and Daniel Day-Lewis - just to see how he does it. I'd be really interested in that."
:: The Reluctant Fundamentalist opens in cinemas on May 10.