Those Wildcats are roaring back with a third iteration of the High School Musical franchise - and the entire cast is heading to the big screen for the first time. Filming is set to begin in March, and breakout star Zac Efron is, unsurprisingly, being rewarded more handsomely than the others. According to one source, the rising star has earned quite the pay jump - he's expected to pocket a salary of more than $3 million. HSM3's plot points are being kept hush-hush, but we've learned that it's centered around the senior prom.