HIGH SCHOOL MUSICAL star Zac Efron insists he is dedicated to his acting career - but isn't prepared to drastically transform his physique for a film role. The 19-year-old star put on weight and dyed his hair black to play heart-throb Link Larkin in Hairspray, but admits he wouldn't go any further to prepare for a role. He says, "It's good to fool around (with your hair). I'm sure I'll change it a lot in the future. I like changing the way I look for roles. I want people to see me in different ways. "(For Hairspray) I put on between 10 to 15 pounds (4.5 - 6.8 kilograms). The weight gain was a by product of dancing and training. I was going for a rounder quality. I tried to bulk up a bit because I going for the Elvis Presley look and he was a bit bigger. I think I managed the '60s look and it's kinda funky. I just had to eat more which was fun. "I would go pretty far, but not too extreme. (Like Christian Bale in The MAChinist who lost 60 pounds) I really admire Bale. I really commended him for going that far. I would go pretty far, but to a lesser degree. I'd be willing to change myself physically to an extent, but not something that would be too destructive to my body."