Rachel Uchitel PLAYBOY: Mistress Going Nude For Magazine

TMZ has learned Rachel Uchitel has signed a deal to get naked for Playboy Magazine -- but there's a full-frontal catch.

Rachel hedged when we asked her about a Playboy offer on TMZ Live on Friday -- but we found out that Tiger Woods' #1 mistress has already struck an agreement. A source close to the mag tells us Rachel has the right to pull out any time before the shoot goes down -- which is in three weeks. We're also told Rachel won't be baring it all -- just the backside ... and the topside.

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