Credit: Charles Eshelman/FilmMagic

Zac Efron really is the lucky one. The Parkland star, 25, is counting his blessings after successfully completing a rehab program five months ago -- where he sought treatment for problems with cocaine and alcohol, multiple sources confirm to Us Weekly.

The former High School Musical actor quietly returned to the spotlight for the Sept. 6 Toronto Film Festival premiere of Parkland, where he was "on his best behavior," an observer noted.

"He realized he needed outside help," one friend explains to Us. "He reached out for it and is doing great now."

With a slate of high-profile film projects on the horizon, Efron is "doing really great professionally," the friend says. "He's in a good place. He's clean and he's happy."

"He just needed to find himself," chimes in a second pal. With Efron acting sometimes erratically on the set of his recent film Neighbors, "His real friends started to worry about him," the second pal concedes.