Jon Hamm has had a rapid ascent to stardom thanks to his role as the quintessential pitchman on AMC's hit Mad Men. Now he's not just playing an ad exec on TV, he's the voice of Mercedes-Benz, the quintessential luxury vehicle.  Having Hamm narrate Mercedes ads is both a no-brainer and a bit of a stroke of genius--he is nearly synonymous with his TV persona. Still, the job wasn't just handed to him. Mercedes considered more than 200 voices, both known and unknown. "Jon Hamm's voice continued to rise to the top," says Donna Boland, Mercedes-Benz USA's manager of corporate communications. "He was able to intuitively interpret the material we gave him with very little direction."  Hamm is one of a growing number of A-list actors who are applying their vocal stylings to advertising. Commercial voice-over work used to be the domain of a legion of unknowns and just a handful of big stars. Sally Kellerman (Hidden Valley Ranch), Martin Sheen (Maxwell House coffee), Donald Sutherland (Volvo) and a few others would fly under the radar with their voice work. Nowadays, nearly every big name in Hollywood is looking to get in on the game.  Other TV stars who have made the leap into voice-over work in recent years: James Spader of ABC's Boston Legal, is the voice of Acura; John Krasinski from NBC's The Office has voiced ads for BlackBerry and Carnival Cruise Lines ( CCL - news - people ); and 24 star Kiefer Sutherland is the calming, reassuring voice behind the Bank of America ( BAC - news - people ) "Bank Of Opportunity" campaign.  While A-listers won't pull in nearly as much as for a major motion picture, voice-overs can be very good money--anywhere from $200,000 to $400,000 up front, plus residuals--for very little time, often no more than an hour. Celebs can lay down audio tracks anywhere they are in the world, provided there's a recording studio. It's not unheard of for a star shooting a film overseas to spend a couple of hours doing a voice-over and then return to the set to get on with the next scene.  The most lucrative deals are for auto and beer commercials, which get heavy rotation year-round during major sporting events. The residuals from the repeat airings can match or exceed the initial guarantee.  Down the food chain, career voice actors can earn $250,000 to $500,000 a year for consistent work, says Treslyn Williams AFTRA's Los Angeles director of commercials. An elite few have pulled down more than a million dollars a year, most notably the late Don LaFontaine, nicknamed "the voice of God," who voiced thousands of movie trailers over the decades.  Of the influx of celebrities doing voice-overs, only a few--less than 10--have made it into the million-dollar club. One is Oscar-winner Morgan Freeman. According to Hollywood insiders, Freeman is being paid somewhere between $1 million and $2 million to be the voice of Visa Debit Cards.  "Morgan Freeman, specifically, was not someone who jumped on the voice-over bandwagon very early on," says Marcia Hurwitz, a veteran commercial voice casting agent and partner at Innovative Artists. "I think it has taken a lot of years for buyers to get someone of his caliber."
Commercial voice-overs were once the domain of disembodied unknowns, but now stars are grabbing the mic--and the money.