In the epic, Bloom plays Paris, the Trojan prince who inadvertently ignites a war by squiring away the wife (Diane Kruger) of a Greek king (Brendan Gleeson.) Bana plays Paris's warrior brother, Hector.
"Orlando got so jealous when he saw Eric Bana's body," Petersen recently told reporters. "He was shocked that very first day (of filming) at Shepperton Studios in London. (Bana) puts his arm around him for the big fight and (Orlando) saw his body and he saw it on the little video screen and he goes: 'Oh, my God! How do I look like?'
"So, he immediately ordered a personal trainer to do whatever he can to put some muscles on because he's rather skinny, Orlando, so that was quite funny," Petersen added/
Bloom, a 27-year-old British actor, is best-known for his performances in "Pirates of the Caribbean," "The Curse of the Black Pearl," and the "Lord of the Rings" trilogy.
"Troy" was No. 1 at the U.S. box office when it opened during the weekend.