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Jo Bros Nick and Joe stepped out with a cute brunette yesterday who looked oddly like an old pal of theirs ... Demi Lovato.

As you know, Joe and Demi dated early last year but by the end of the year when Joe was hooking up with Ashley Greene, Demi was getting buck wild beating up back-up dancers which ended with her entering rehab a "treatment facility."

So who's this new girl the brothers are spending time with?