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Kara DioGuardi and "Bikini Girl" Katrina Darrell faced off again on last night's American Idol finale.

The duo famously sparred during tryouts, when DioGuardi trashed Darrell's rendition of Mariah Carey's "Vision of Love" -- and then burst into the tune herself. Darrell then slammed DioGuardi's version, before Simon Cowell and Randy Jackson voted her through.

On last night's show, Darrell showed off her bikini bod once again -- and noticeably larger breasts.

Joked Ryan Seacrest: "I'd ask what's new, but I already know!"

Darrell broke into her infamous Carey song -- and appeared surprised when DioGuardi suddenly joined her for a duet.

At the end of the song, DioGuardi ripped off her dress to reveal her bikini bod -- and Seacrest announced they dared her to in exchange for a donation to her favorite charity.

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