Brad Pitt came on board having lost weight, grown a long beard and dyed his hair brown for another film that fell through — so he worked out for six months to get into the shape required for the role. He also had to quit smoking during production.
Garrett Hedlund likewise gained 30 lbs. The rest of the male actors all had to shave and wax their chests completely.
Dueling Works: With Alexander, another historical Ancient Greek costume war epic with a big-name cast. While it had a mixed reception, Troy was much more successful grossing over $497 million at the box office unlike Alexander which bombed with critics and audiences.
Fatal Method Acting: George Camilleri, a bodybuilding extra, broke his leg while filming an action sequence at Għajn Tuffieħa. He was operated on the following day, but suffered complications and died two weeks later.
It kind of sucked. He's dead, so I can say that. But he wasn't the most pleasant person. He was just a drunk, and Peter O'Toole. You know, he had a two-day part, and I played Helen of Troy and he was Peter O'Toole, and he just wanted to make sure that everybody knew that he was Peter O'Toole. And he could barely make it up the stairs. We were on a set that was - you know, you have to climb, like, I don't know, 100 steps to go up. He was just - first of all, everybody thought he was gonna die right there and then. Because it was, you know, 120 degrees, and he had to walk up 100 stairs. And he was very old, and very drunk.
No Stunt Double: Brad Pitt and Eric Bana did not use stunt doubles for their epic duel. They made a gentlemen's agreement to pay for every accidental hit; $50 for each light blow and $100 for each hard blow. Pitt ended up paying Bana $750, and Bana didn't owe Pitt anything.
Troubled Production: Tamer than most examples but still troubled. Filming happened in Morocco at first but had to be moved due to the impending Iraq war. Filming in Malta also led to the set being besieged by paparazzi trying to get pictures of Brad Pitt and Orlando Bloom in particular - the noise from their helicopters rendering several takes unusable. Filming then happened in Mexico, where two hurricanes tore through the sets, and marine biologists had to be on hand to ensure the safety of the area's endangered turtle population. Many stagehands also fainted in the intense heat. The destruction of the sets and Brad Pitt injuring his Achilles tendon led to filming being postponed until December, meaning even less time to shoot than before, inflating the budget even further. Wolfgang Petersen confessed that most of the CGI budget went towards digitally erasing the long shadows in outdoor scenes.
Wag the Director: Wolfgang Petersen asked Peter O'Toole to tone down his famously posh accent, but he refused.
Before Wolfgang Petersen came on board, Christopher Nolan was the one being eyed for the director's chair, having just scored a Breakthrough Hit with Memento. Ironically, the former was considering between Troy and the script that would eventually become Batman Begins.
Composer Gabriel Yared originally worked on the score for over a year, and Tanja Carovska provided vocals on various portions of the music (as she later would on James Horner's score). However, reactions to the unfinished score at test screenings were negative, stating that it sounded too "old-fashioned", and in less than a day Yared was off the project without a chance to fix or change his music. James Horner composed a replacement score in about four weeks. However, Yared's music was later restored for the Director's Cut.
Helen was actually meant to be The Ghost early in production. Word of God is that - due to her status as the World's Most Beautiful Woman - it would be impossible for anyone to live up to audience's expectations. Producers insisted Helen had to appear in the film, and Nicole Kidman was who the studio was favouring. Wolfgang Petersen however felt casting an unknown would be better.
The Greek Gods were originally in the plot, following the mythology. The director chose to drop them, opting for a Demythification interpretation. The exception is Thetis, though the film never states if she's meant to be a goddess or not (Achilles does claim to have seen the gods later in the film).