NEW YORK—Four actors from “Grey’s Anatomy,” the ABC hit where Isaiah Washington was fired for anti-gay slurs, are featured in a new ad campaign preaching tolerance for gays and lesbians.

The Gay and Lesbian Alliance Against Defamation released 25 new public service TV ads Sept. 4. T.R. Knight, Sara Ramirez and Kate Walsh of “Grey’s Anatomy” all made ads. Alexandra Billings, a transgender actress who appeared in one episode of the medical drama, also participated.

“Be an ally. Be a friend,” tennis star Martina Navratilova says in one of the spots, echoing the campaign’s theme.

A handful of cable networks, including the Sundance Channel and Lifetime, have agreed to run the ads and GLAAD is urging more to participate, Romine said.

Actors Rachel Griffiths, Marlee Matlin, Rebecca Romijn and Lance Bass are among the 21 other celebrities featured.