British rock star Chris Martin leapt onto the Washington stage, driving screaming fans wild as he belted out one crowd-pleasing hit after another.

As dazzling lights and glitter burst around the charismatic Coldplay frontman, captivated fans could have been forgiven for missing the "Make Trade Fair" logo inscribed on the singer's piano at the concert.

But if the hundreds of signatures collected by Oxfam volunteers during the Washington show this month were any measure, the message was not lost.

While using celebrities to front charitable campaigns is not new — the 1985 "Live Aid" concerts for Ethiopian famine victims made it cool to care — putting famous faces to work on dry-as-dust trade issues is a fresh idea.

Movie stars Brad Pitt and Heath Ledger are among those who have expressed an interest in trade and the developing world.

And with global trade talks going down to the wire before a year-end deadline for a deal, the big names may multiply.

"Having Chris Martin and Coldplay be frontmen for 'Make Trade Fair' has elevated the trade debate (and) piqued people's interest. Politicians realize the world is watching," said Oxfam spokeswoman Lyndsay Cruz.

The current Doha round of trade talks between nearly 150 member countries of the World Trade Organization has limped along for 4 1/2 years.

So far, little progress has been made on a pact to lift millions out of poverty and boost the world economy by slashing subsidies and tariffs that hobble international trade.

But now there is new urgency: in mid-2007, President Bush is due to lose his power to approve trade deals with minimal congressional involvement, which would make any eventual deal agreed after then harder to ratify.

So the world's trade ministers are hastily scheduling extra meetings and urging their peers to take action. Meanwhile, development agencies are pressing celebrities into service.

In the past month, lobbyists in Washington have been abuzz with talk that Irish rocker Bono — fresh from a successful campaign to urge world leaders to cut developing world debt — would take on the WTO, adding his voice to numerous agencies pushing rich nations to make more concessions and cut a deal.

Jamie Drummond, executive director for Bono's lobby organization DATA — Debt, AIDS, Trade, Africa — said the group was planning a "lot of stuff," but gave no details.

"Sometimes it's when you get celebrities to get engaged in the details of what is normally considered boring ... and the public get engaged — and you can actually make change happen," Drummond said.

"When even a celebrity can get some arcane part of trade policy legislation, then the congressmen and the Brussels-based bureaucrats had better get it too," he added, referring to the European Union headquarters.

But not everyone is convinced that bringing famous faces into the debate is the best way to get fast results for the world's poorest countries.

Exploiting Fame?

The WTO deal being discussed is a complex tangle of formulas and trade-offs, with countries at different stages of development bringing their own domestic pressures to the mix. Reducing it to a catchy sound-bite that an actor or singer can trot out does the process an injustice, some say.

"These stars are extremely well intentioned and think charities must have exactly the right attitudes — but the charities are exploiting them," said Jagdish Bhagwati, professor of economics and law at Colombia University and senior fellow at the Council on Foreign Relations.

Bhagwati also accused some aid groups of over-simplifying the trade debate and singled out Oxfam, which he said was wrong to ask rich nations to liberalize while insisting developing countries should not have to.

"When they say that subsidies should be removed, they do not distinguish between those which don't distort trade (and those which do). So they are muddying up the debate," he added.

Nonetheless, marketing experts say that in today's celebrity-obsessed world, endorsement of a simple message by someone who appears regularly in People magazine is vital. And the message need just be enough to start the public thinking.

"You have to distill and reduce your message to the point that it becomes a good headline. On the basis of that good headline, you hope that people will be intrigued to dig further," said John Barker, president of New York advertising firm DZP Marketing Communications.

"Without a famous face to front their cause, these organizations lack media attention, glamour and, with the more everyday contributor, credibility."