The Octagon king, who fought Floyd Mayweather in the boxing ring last August, is expected to make his return to UFC in September.
The “Notorious”, who was recently unveiled as the new face of Burger King, could face either Tony Ferguson or Khabib Nurmagomedov.
And McGregor has left his loyal legion of fans on tenterhooks with his tweet.
He tweeted: “Stay ready.”
However, it was not clear what he was referring to.
Meanwhile, WWE legend John Cena has hinted he would jump at the chance to take on McGregor in a wrestling ring.
He told social entertainment publisher The Hook: “Would I ever be up for getting in a ring with Conor McGregor?
“Absolutely, but that would mean he would have to be up for getting in a WWE ring.
“Let’s not put the cart before the horse ladies and gents.
“Let’s see what Mr McGregor wants to do and then figure it out from there.
“I’m not the one to hand out invites, I don’t do that.
“That’s not in my job description, that’s going to be up to him.”
