Actor Martin Sheen will film a public service announcement on behalf of the “Campaign to Eliminate Conflict Diamonds,” organizers confirmed.

He will also voice public support for the campaign.

”He’s one of the celebrities we have,” says Rory Anderson, governmental relations manager of World Vision, the Christian humanitarian group that’s a driving force behind the campaign. ”I won’t say more, as I’ve got to keep at least one ace up my sleeve.”

Sheen is best known for playing President Josiah Bartlet on NBC’s ”The West Wing.”

Sheen’s involvement is a signal that the NGOs plan to jump-start their consumer campaign on conflict diamonds, which has been largely quiet since Valentine’s Day. Industry officials fear the campaign will hurt demand for diamonds.

Sheen is scheduled to speak on the issue this summer at the National Press Club. Anderson would not comment on future plans to use Sheen.

JCK