at Drake's Grammy Party
Former "Celebrity Apprentice" contestant Claudia Jordan told police ... she was attacked by a crazed woman who's currently involved with her ex-husband ... and it all went down at Drake's Grammy after party.
TMZ has learned ... the actress/former "Deal or No Deal Model" claims she was at Drake's party at Greystone Manor in L.A. when the woman assaulted her out of nowhere -- taking a swing at her and connecting with the top of Claudia's head ... in the middle of the nightclub.
According to Claudia, her ex recently broke up with the woman in question -- and for some reason, she blamed Claudia for things going sour. Claudia says she hasn't spoken to her ex in two years.
Claudia tells TMZ ... she didn't say a word to the woman the entire night -- but the unidentified female was staring daggers at her the entire time ... before eventually losing it.
Security at the club was notified and the woman was tossed out.
Claudia tells us, she filed a police report with the LAPD -- and went to the hospital Monday to have her head and neck checked out.