Irish mixed martial arts fighter Conor McGregor announced on Twitter that he has accepted a fight against American Dustin Poirier. "I accept, Jan 23rd is on! My goal is to see this fight take place in Cowboy stadium. Proper Style!" McGregor tweeted. Last month, the 32-year-old tweeted he would be coming out of retirement to fight 41-year-old boxer Manny Pacquiao.