EXCLUSIVE

Hold on to your singlets, because Sting tells TMZ he wants to WRESTLE at WRESTLEMANIA ... even though his new contract with WWE is just a video game deal ... and he's even got an opponent in mind.

It's HUGE news ... considering the ex-WCW legend has never stepped inside a WWE ring before in his nearly 30-year career.

Sting tells us he's pumped about his new business relationship with the McMahon family -- which came together so Sting could be a playable character in the upcoming WWE2K15 video game.

But he doesn't want the relationship to end there -- Sting says he wants to hammer out a deal so he can face off against Undertaker at Wrestlemania 31 in March 2015.