Fast_Five

Summer begins this Friday, according to the tagline for "Fast Five." But wrestler-turned-action star Dwayne "The Rock" Johnson has been getting his imposing beach body ready for some time now. A newcomer to the "Fast and Furious" franchise, Johnson bulked up his already considerable musculature by 30 pounds for the fifth entry in this series, which finds returning stars Vin Diesel and Paul Walter moving from the world of underground drag racing to rip off a crime lord's stash in Rio de Janeiro. To bulk up for this high-octane heist flick -- not to mention his climactic onscreen brawl with Vin Diesel -- Johnson stuck to a diet and workout routine that involves weightlifting, curls and a low-carb diet. Building on the ripped biceps he sported in last year's vengeance flick "Faster," The Rock is now armed (pardon the pun) with some serious guns for this summer blockbuster. According to screenwriter Chris Morgan, The Rock is "not a villain, but a man who will do whatever it takes [to bring in the series' outlaws]... dead or alive." Photos: Dwayne Johnson on the red carpet >> Johnson then and now Everett Collection/Universal Pictures To make Johnson a threatening opponent for the famously-ripped Diesel, The Rock regained some extra muscle mass he carried in his wrestling days-weight he lost, in fact, when he made his transition to Hollywood in the first place. Back around in 2004, closer to years he reigned as the "Scorpion King," Johnson told Men's Health how his trainer helped him cut down on his body mass for Hollywood roles by decreasing his cardio and increasing the number of particular body part-centric workouts. For much of his '00s -- which included several turns in family films -- Johnson was a slimmer muscle man. The kind you might find around your local gym. Video: Johnson fights Diesel in 'Fast Five' >> 'The Rock' in his wrestling days Everett Collection For "Fast Five," Johnson has nearly returned to his hulking size circa his WWF/E days. Focusing on his abs with weight work and a strict six-day-a-week diet (he gives himself one cheat day), The Rock has returned to a muscle mass that makes him more than a match for his very-physical onscreen showdown with Vin Diesel. "Fast Five" opens this Friday. Watch an exclusive interview with Dwayne Johnson and Vin Diesel in Rio de Janeiro below.