NEW YORK – “Bright. Crisp. Clean. Pure,” says the silky smooth, perfectly masculine voice on the beer commercial. “This is Budweiser. THIS is beer.”

Quick, who is that? Hint: It’s a big movie star. Though his name’s never mentioned, the makers of Budweiser are banking on the fact that you’ll get it eventually – and that you’ll say “Wow!” when you do.

Twenty years ago, voiceovers were the domain of the baritone radio announcer or the character actor. No longer. These days, more A-list stars than you might imagine are cashing in.

Kevin Spacey’s pitching Honda. Kelsey Grammer does Disney. Kiefer Sutherland voices Apple commercials, and his dad, Donald, did Volvo. There’s Queen Latifah (Pizza Hut), Sean Connery (Level 3 Communications), Christian Slater (Panasonic), Gene Hackman (Oppenheimer Funds) – oh, and then there’s Julia Roberts.

That’s right, Julia Roberts, in a recent campaign for America Online.

It seems no one’s too rich or famous to do a voiceover. It’s not too hard to see why the celebs like it: it’s an easy, lucrative form of work – a few recording sessions where you can show up with messy hair and no makeup. The more difficult question is why advertisers are willing to spend a huge chunk of their budget on a star whose voice, however distinctive, likely won’t be recognized by many.

“Honestly, sometimes I’m mystified,” said Maureen Kelly, a casting director who’s worked in the voiceover field for two decades. “I guarantee you most people couldn’t tell the AOL voice was Julia Roberts. I’m just not sure why advertisers spend this astronomical amount of money when the voice isn’t even identifiable.”

By astronomical, we’re talking seven figures, easy. Although companies won’t say how much they pay, industry experts say a megastar like Roberts would have to make well into that range.

Or George Clooney, that mysterious Budweiser voice. When Anheuser-Busch was searching for “a classic voice” last year, the company hit on Clooney as the perfect embodiment of its product. “George Clooney – it’s almost a brand in itself,” said Dan McHugh, vice president for trademark brands. “It just made a lot of sense for us.”

The idea, said McHugh, is that the consumer will “sort of know the voice. They may not necessarily place it right away, but when they do, they say, ‘Wow'”! It’s that whole intrigue of discovery.” In other words, the “cool” factor is higher because there’s mystery involved.

Laura Cheshire, a commercial director in New York, said many celebrities have distinct vocal patterns that set them apart – recognized or not.

“They have a special authority, even if you can’t name them on the spot,” said Cheshire. “It’s usually worth the expense, because you get more emotion – which sells more product.”

Advertisers didn’t always have such an array of choices. Twenty years ago, said Linda Weaver of the Access Talent agency, jobs went primarily to announcers from the radio world.