( CNN ) -- To convincingly yell `` I am Hercules ! '' in his new action movie , Dwayne `` The Rock '' Johnson had to do more than warm up his vocal chords . As a former pro wrestler , The Rock was already approaching Greek demigod territory in terms of build , but even he had to change his diet and exercise to become mythologically ripped . According to USA Today , the 42-year-old actor had to endure a `` Hercules diet '' that consisted of seven meals a day , extremely heavy on protein . The Rock would start with a hearty breakfast of four egg whites , five ounces of oatmeal and a 10-ounce filet of steak . By meal No . 3 , he 'd have wolfed down another eight ounces of chicken breast ; eight ounces of halibut ; two cups of white rice and two cups of a green vegetable , like broccoli or asparagus . Meals four through six were essentially more of the same , with a few baked potatoes thrown in instead of rice . It sounds like a lot -- and that would be because it is -- but The Rock told USA Today the diet was pretty painless . `` The only tough one was the last meal of the day , No . 7 , '' he said , referring to the nightcap of 10 egg whites scrambled with vegetables , plus 30 grams casein protein . `` I get back to the hotel room , I 'm ready to go to sleep . But I have to down 10 egg whites . '' But it sounds like eating those eggs was like downing cake compared to the workout portion of his Hercules training plan . `` It was grueling , '' The Rock told CNN of his training plan at the `` Hercules '' premiere in Los Angeles on Wednesday . `` It was for six months , and then it was for an additional six months once I got ( on set ) , '' the actor said . `` So it was the most challenging role that I had ever taken on -- physically and mentally , but I 'm happy to be here and I 'm happy to know the movie 's good . '' The Rock 's not just hyping his project . According to RottenTomatoes.com , `` Hercules '' was 70 % fresh as of July 24 . Directed by Brett Ratner , the movie follows Hercules into war as he tries to protect the King of Thrace . Also starring John Hurt and Ian McShane , `` Hercules '' opens Friday . Comic-Con : Ben Affleck 's 'Batman ' makes an appearance . More 'Iron Man ' ? Sounds good to me , Robert Downey Jr. says . Dwayne Johnson maybe just revealed he 's playing a superhero . CNN 's Topher Gauk-Roger contributed to this report .
Dwayne ` ` The Rock '' first appeared as the titular character in ` ` Hercules '' He had a ` ` ' '' life plan , and ate seven meals a day . He called the role the most challenging he 's ever taken on .