Irish mixed martial arts (MMA) star Conor McGregor is set to reverse his latest flirtation with retirement with a fight against American MMA fighter Dustin Poirier in January, he said on Thursday.

A statement on McGregor's news website, TheMacLife.com, said the 155-pound contest would take place on January 23, with Abu Dhabi in the United Arab Emirates being the likely venue.

The website said McGregor had signed his agreement to fight as the main event on UFC 257. Poirier has also signed up for the bout.

"I am very grateful to be about to return and get to do what I love again," McGregor was quoted as saying.

"I look forward to the fresh test Dustin will bring since our first bout, while also showcasing my own incredibly deep cache of weaponry. Whatever tool is needed on the night will be pulled from the duffel."

McGregor, who defeated Poirier via a first-round knockout in 2014, has not fought since January when he defeated Donald Cerrone in 40 seconds.

A frustrated McGregor, who had previously announced multiple retirements before returning to the octagon, said in July he had retired.

However few took the pledge seriously, and McGregor continued to be linked to a possible cross-combat fight with Filipino boxing icon Manny Pacquiao before the Poirier bout was confirmed.