Nicole Richie is stepping up as Paris Hilton's best pal by diverting female attention away from rocker Benji Madden.

Nicole - who is dating Benji's twin brother Joel - has been batting away blonde babes from the Good Charlotte frontman following his split from Paris.

A source says, "Benji was approached by dozens of ladies. Girls were trying to flirt with him . . . but Nicole kept getting in the way."

Benji and Paris split last week with a heart broken Paris waiting only a few days before publicly declaring her undying love for her rocker ex.

Paris told The Sun, “Just the thought of dating someone else grosses me out. No way.”

See Hollywood's odd couple below