The Hollywood actress was pregnant with her first child with husband Javier Bardem while she shot the action blockbuster with Johnny Depp.
Cruz's belly swelled rapidly during the shoot and the costume designers had to work hard to keep refitting her outfits.
She tells the Associated Press, "I just had a new fitting every three weeks. We kept having fittings, but they were very, very kind to do it."
Director Rob Marshall also had to use numerous body doubles to fill in for Cruz to disguise her pregnancy, but admits all the extra work was worth it because he was determined to have her onboard: "We were very clever how we shot her. It took more time, but it was worth it... There was only one person. That was Penelope. So we knew that we'd rather work with her and make it work, because she was so right for the role."