"Me and Orson Welles" won't be remembered for its "me," but for its remarkable Orson Welles.

Zac Efron is the Me, playing a plucky New York kid named Richard Samuels who bluffs his way into a small role in Welles' legendary 1937 staging of "Julius Caesar" at the Mercury Theater in Manhattan.

British actor Christian McKay is Welles, and he's so stunningly good as Welles - he gets both his physical essence and his spirit - that all else fades to the background.

All else is a lot of filler about Samuels and his eventful coming-of-age. He has an improbable romance with Welles' secretary (Claire Danes), a notoriously hard-to-get blonde who's pursued by almost every actor in the Welles troupe, including Joseph Cotten (James Tupper).

The eager Samuels also becomes something of a mascot to Welles, who pulls Samuels aside for advice and allows him to tag along on spontaneous adventures.

This leads to a bravura sequence wherein Welles abruptly leaves "Caesar" rehearsals, tears across town in an ambulance (so he doesn't have to stop at lights), sirens wailing, to make an appearance on live radio.

Director Richard Linklater shoots the entire sequence in only a few takes, and McKay captures Welles' manic genius - he's candid and confessional in the ambulance, then charming and flirtatious on his way to the show (he performed impromptu magic, and was a natural showman), then brilliantly improvisational during the program itself.

Which of these is the real Welles? Did he reveal himself to Samuels, or was it all just another rehearsal?

The movie shows Welles willing to adopt any persona - friend, foe, advocate, bully - in order to bring his troupe into the proper opening-night crescendo, wherein everyone's emotions are at their most transparent.

This is Linklater's contribution to the recent/coming spate of movies ("Broken Embraces," "Nine") about collaborative art, and when it works - when it's focused on the Welles/McKay dynamic and enigma - it's the best of the bunch.

Produced by Richard Linklater, Marc Samuelson and Ann Carli, directed by Richard Linklater, written by Holly Gent Palmo and Vince Palmo Jr., music by Michael J. McEvoy, distributed by New Line Cinema.