"I accept, Jan 23rd is on! My goal is to see this fight take place in Cowboy stadium. Proper Style!", the fighter wrote on Twitter.
McGregor had announced his retirement from the sport earlier this year, his third time doing so. Early discussions for an exhibition fight for charity with Poirier became official when the UFC offered to officiate.
"Manny next", McGregor said in his tweet, indicating that he intended to don boxing gloves against Filipino boxing legend Manny Pacquiao.
Uncertainty loomed over McGregor's return to the octagon as he had insisted on fighting Poirier in 2020, but UFC President Dana White set 23 January as the earliest possible date. McGregor and Poirier last met in 2014 in UFC 178, with the Irishman prevailing on a technical knockout. The Notorious boast a record of 22 wins and four losses, while Poirier has a 26-6 record.
McGregor's last fight took place in January, where he knocked out veteran fighter Donald Cerrone in under one minute. Before that, he suffered high-profile back-to-back defeats against top brass fighters: Khabib Nourmagomedov in the octagon and Floyd Mayweather in the ring.