4th Alleged Tiger Woods Mistress Lawyers Up

Another woman is coming forward claiming she had a long-term affair with Tiger Woods ... and to prove she means business, she's already hired herself a lawyer.

TMZ has learned the alleged mistress -- that's number four on your scorecards -- claims this relationship didn't originate in Vegas, it started near Tiger's home in Orlando.

The woman -- a former VIP cocktail server (sounds familiar) -- has hired Orlando attorney Michael O'Quinn to address the media with her story very soon.

We're told the woman claims she began having the alleged affair with Tiger back in 2004 -- when she was 20-years-old -- and insists the affair lasted for more than two years.

Stay tuned ...