Dr. Dre Mercilessly Attacked In Case of Alleged Mistress

Dr. Dre's attack against a big website may have backfired ... the attorney for TheDirty.com fired off a letter to Dre saying what a big fan he is ... and then lumping the legendary rapper in with the likes of OJ Simpson.

It's actually pretty hysterical. A post on TheDirty claimed Dre -- who is married -- has been hooking up with a big booty video vixen.

Dre's lawyer fired off a letter to TheDirty, and we've obtained the response from the website's lawyer, and it's priceless.

David Gingras, Esq., begins by saying, "Back in the '80s I personally destroyed many subwoofers blasting N.W.A.'s 'F**k Tha Police' in my car in the high school parking lot."

Gingras goes on to say what a fan he is ... and then goes on a very sarcastic attack.

First, the lawyer challenges Dre's claim that the story is false: "Bill Clinton and Monica what's-her-name both denied having sexual relations. Of course, they were both lying. Same thing with Lance Armstrong." And then he jokes, "Other than O.J. Simpson, who was clearly framed, history is filled with examples of people who make mistakes and lie about them to cover it up."

The hired gun goes on and on, making jokes about people in Eastern Kentucky -- "cue banjo music," trashing a court decision from that region that makes it seem Dre has a case. The lawyer wrote, "If you believe the Kentucky court's decision [it's compelling] ... I also have a fabulous ocean-front unicorn ranch here in Arizona that you might want to buy."

Bottom line -- TheDirty's lawyer says the posts in question were comments from users, and the website isn't responsible.