Zac Efron taking on the role of Ted Bundy is such dead-on casting, it could be the role Zac is ultimately remembered for ... according to the man who defended the infamous serial killer.
John Henry Browne, Bundy's lawyer in the '70s and early '80s, tells TMZ ... Efron's background as a charming heartthrob gives him an edge tapping into Bundy's persona -- the smooth talking, good looking guy who seduced young women.
That's the easy part, though. Browne says Zac's real challenge will be capturing the Bundy's "essence of evilness." He says if Zac can nail that, it would be such a departure ... it could make his career.
The lawyer says he had meetings about turning his book, "The Devil's Defender," into a TV series ... and Efron's name also came up then.
As for which Bundy flick will be better -- Efron's "Extremely Wicked, Shockingly Evil and Vile" or Mark Harmon's 1986 TV movie, "The Deliberate Stranger" -- Browne's picking Zac.
But only because Harmon's script kinda sucked.