Actor/director/producer Rob Reiner tells volunteers how to be more convincing in this campaign ad, released Tuesday by Sen. Hillary Rodham Clinton's (D-N.Y.) '08 presidential campaign.

Reiner has directed, produced, and appeared in television and film since the 1960s. He directed "The American President," and appeared in "Primary Colors," the film version of a book based on Bill Clinton's first presidential run.

Reiner has given money to both Clinton and former Sen. John Edwards (D-N.C.) in their bids for the '08 presidential nomination, according to The Hill's examination of Federal Election Commission filing reports.