MTO WORLD EXCLUSIVE: Guess Which MARRIED Celebrity . . . Was Spotted Getting COZY . . . With Lil Wayne's EX-WIFE TOYA!!!!

MediaTakeOut.com got a juicy bit of tea for y'all. Toya Wright held a Halloween/Birthday party two nights ago in Atlanta - for "Pimps And HEAUX." And people are saying that she was ALL OVER R&B superstar Usher.

According to one of our to snitches, Lil Wayne's ex and Usher were canoodling almost like a couple. The insider explained, "It was almost like they were dating. Toya was all out in the open with her flirting. I don't know where Usher's wife is, but she needs to have a talk with Toya. That was uncalled for."

Earlier in the summer, there were reports that Usher and wife Grace hit a rough patch in their marriage. The couple HAS been seen out together, however. Most recently Grace attended Usher's Star On The Walk Of Fame ceremony with her husband.