Director had Reilly in mind all along

He comes down the stairs to the backstage area of San Francisco's Great American Music Hall dressed as a stylish civilian — plaid shirt, suede jacket — but the occasional bleats of sound check and the massive stacks of gear serve as reminders that he isn't just an actor playing a musician in a movie. He'll take the stage later that night as Dewey Cox, the imaginary, legendary master of all popular 20th-century musical forms, as part of an 11-date publicity tour for the new movie "Walk Hard."

Reilly calls the tour "super fun" but admits to a bit of wear. "Filming the movie and recording the music for the movie took everything I had, in terms of being an actor and learning how to be a musician," he says. "And doing these shows has required a whole other level of energy output."

A few years ago, when Reilly played the cuckolded husband in the screen adaptation of the musical "Chicago," his career seemed to be summed up in his solo number, "Mr. Cellophane." The lyrics — "Mister cellophane/ 'cause you can look right through me/ Walk right by me/ And never know I'm there" — pointed to Reilly's status as an award-winning actor without significant name recognition.

That has changed. Perhaps a better way to identify Reilly is through the nickname he came up with for Dewey Cox: the Chameleon.

Over his career, Reilly has slipped into a wide variety of parts with ease, and worked with many accomplished directors and actors. After beginning his film career with a principal part in Brian De Palma's "Casualties of War," he become a favorite of Paul Thomas Anderson ("Hard Eight," "Boogie Nights," "Magnolia"), was in two Martin Scorsese films ("The Aviator" and "Gangs of New York"), got an Oscar nomination for his role in "Chicago" and worked with Robert Altman in "Prairie Home Companion." He's been happily married for 15 years to Alison Dickey, an independent producer he met on the set of "Casualties." They have two children.

"Walk Hard" marks the second time Reilly has been cast as a leading man — he played a con man in "Criminal" (2002), a little-seen remake of an Argentine caper, "Nine Queens."

Reilly has shown that his comedic chops are on par with those of the best improvisers in the business; he had a memorable turn as Will Ferrell's second banana in last year's popular NASCAR spoof, "Talladega Nights," and has been a recurring character (Steve Brule) on Adult Swim's "Tim and Eric Awesome Show."

For the role of Dewey Cox, director Jake Kasdan says there really was no other candidate. "At the absolute earliest stage of the project, he was the only person we talked about," Kasdan says. He says Reilly's serious approach to comedy elevated the whole endeavor.

"It was as real an acting job as I've ever had to do," Reilly says, "with the emotional stuff — we're talking about drug addiction or a long-lost son or begging for your life in prison."

The process of making "Walk Hard" was complicated by the fact that Dewey Cox needed a body of songs that would be funny but would also sound good. And, as befitting the ridiculous notion that Cox had successfully gone through every 20th-century musical cliché — the blues, the Elvis sound, the Roy Orbison crooner period, through to Dylan and psychedelia and even into punk — the songs needed a variety of songwriters.

Kasdan, Reilly and a team of musicians (with help from songwriters Dan Bern, Marshall Crenshaw and Mike Viola) spent six months in the studio hammering out the Cox sound before filming began. Reilly says the Dewey Cox character was shaped in those recording sessions, and Kasdan says he's never worked more closely with an actor than with Reilly during that time.

Every few years, another music mockumentary comes out in the mold of the faux-metal skewering of "This Is Spinal Tap." But "Walk Hard" aims for a slightly different target: the bloated Hollywood fictionalization of a musician's life, complete with a loyal first wife, relentless womanizing, drugs, depravity, rehab and the redemptive love of a good woman.

Biopics have been a staple of filmmaking forever, but the success of "Walk the Line" and "Ray" made the self-serious, heavy-handed exposition impossible for Kasdan and Judd Apatow to resist poking fun at.

Reilly's next projects are a drama ("Quebec") and a reteaming with Ferrell for a comedy called "Step Brothers" that he co-wrote, which he describes as " 'Ordinary People' meets 'Talladega Nights.' " He also has signed up for "Cirque du Freak," based on a popular teen fantasy series.

"I'm just trying to stay ahead of people's expectations, so they don't get bored with what I'm doing," he says, with a winking smile.

"Filming the movie and recording the music for the movie took everything I had, in terms of being an actor and learning how to be a musician."

John C. Reilly