Ashanti Brings Out Nelly During Her Las Vegas Concert

Ashanti was certainly serving body onstage, and she made sure she didn't do it without her rumored boo ... bringing out Nelly as a surprise guest during her show!!

Ashanti hit the stage with Ja Rule in Sin City for their show at the Palms Casino Resort on Sunday. However, fans were in for a treat once the singer brought out her very special guest.

Nelly and Ashanti performed their throwback jam, "Body On Me" ... and she definitely put her body on Nelly, while showing off her dance moves. And, fans ate up the whole thing ... cheering as they serenaded each other on stage.

As we reported, fans began to speculate they might have recently rekindled their romance ... since they've been hitting up events together, like the Garcia/Davis boxing match last month. And, it's especially hard to argue now!

Of course, these 2 go way back -- they dated in the 2000s, so fans seemed super hyped to see them spending more time together as of late.