• by kyle , Daisy Whitney , July 29, 2005

Catherine Zeta-Jones is the well-known face of t-mobile, but she's not the only celebrity padding her bank account with endorsement work. Last year, Alec Baldwin served as the voice of Disney World in a commercial, while Robert Redford spoke for United Airlines, and Julia Roberts for America Online.

About 10 percent of commercials feature celebrity spokespeople, and 20 percent of ad dollars are spent on such campaigns, according to Jonathan Holiff, president of the Hollywood-Madison Group, an agency that recruits celebrity spokespeople.

Stars have trekked to Europe and Japan to pitch products in the past, but in recent years consumers here have come to accept celebrities shilling. However, feedback is mixed on these ads' effectiveness. One study found that 72 percent of people who bought a celebrity-endorsed product did so because of the star's seal of approval, but a recent Ipsos study indicated celebrity ads score lower on persuasion and related recall.

Celebrities benefit, though. Actor Billy Crudup's longstanding gig as the voice of Mastercard has allowed him to pursue stage work and smaller films. That's priceless.