The Whole Truth is taking aim at cougars.

Annabella Sciorra, who played Tony's crazy mistress on The Sopranos, will guest-star in ABC's new legal drama as a cougar on trial, TVGuide.com has learned exclusively.

"She's fabulous," executive producer Tom Donaghy says. "She just signed on to do [an episode called] 'When Cougars Attack,' in which a high-fashion designer is accused of murdering her young lover."

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The 46-year-old actress, also known for her roles in The Hand that Rocks the Cradle, Mental and Law & Order: Criminal Intent, will appear in Episode 6 of the show's first season.

Judd Hirsch, who co-starred with Truth's leading man Rob Morrow in Numb3rs, was the first to sign on to guest-star, but Donaghy hopes the pair won't be the last. "I want to cast all my famous friends," he says with a laugh.