Hilary Duff has signed up to front a new ad campaign aimed at shaming teenagers into becoming more respectful towards gay men and lesbians.

The pop star/actress has teamed up with America's Gay Lesbian & Straight Education Network to star in a new public service announcement.

In the ad, Duff swoops on two shopping teens when one of them describes a bad dress as "so gay," stating, "You know, you really shouldn't say that something's gay when you mean it's bad - it's insulting."

Duff says, "Nobody says it meaning to hurt someone's feelings but it can really make an impact on someone."

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(This news article provided by World Entertainment News Network)