Hollywood celebrities Roseanne Barr and Martin Sheen have endorsed anti-war activist Cindy Sheehan in her longshot bid to win Rep. Nancy PelosiNancy PelosiVulnerable Democrats tout legislative wins, not impeachment Photographer leaves Judiciary hearing after being accused of taking photos of member notes Overnight Health Care — Presented by That's Medicaid — House passes sweeping Pelosi bill to lower drug prices | Senate confirms Trump FDA pick | Trump officials approve Medicaid work requirements in South Carolina MORE's (D-Calif.) seat.

Other celebrities who have endorsed Sheehan include actor Sean Penn and singers Melissa Etheridge and Willie Nelson.

Sheehan, who is running as an independent, has challenged the Speaker to a debate, but Pelosi has not agreed to one.

Sheehan told The Hill in 2007 that attracting celebrity backing would be a key facet of her campaign.

Pelosi has received political donations this cycle from actor Robin Williams, writer Aaron Sorkin, producer Steve Bing and golf course architect Robert Trent Jones.