'Mystic Mac' is back!... and not for the first time.

Conor McGregor steps back into the Octagon having not fought since knocking out Donald Cerrone after just 40 seconds at UFC 246 over 12 months ago.

That was supposed to be the first of three fights in 2020 for a rejuvenated McGregor, who had spent 14 months away following the ugly melee that followed his loss to Khabib Nurmagomedov in October 2018.

Then, of course, a global pandemic caused chaos to the world of sport and, in June, McGregor announced he was retiring from fighting, citing he was just not excited about the MMA game.

Fans of McGregor and the UFC had been here twice before and the scepticism that met his announcement was justified when it was confirmed the big-talking Irishman would face off against Dustin Poirier for the second time in his career.

Ahead of that bout on Fight Island in Abu Dhabi this weekend for UFC 257, we take a look back at McGregor's past 'comeback' scraps.

August 20, 2016 – McGregor beats Diaz by majority decision

In March of the same year, McGregor suffered his first loss fighting in the UFC after submitting to a rear-naked choke from Nate Diaz at UFC 196.

McGregor was slated to have his rematch against Diaz at UFC 200 but in April posted on Twitter: "I have decided to retire young. Thanks for the cheese."

Two days later, he clarified that he had not actually retired but had fallen out with UFC bosses over promotional work and the fight was pulled.

But the bout was eventually staged at UFC 202 in an absolute classic that saw McGregor avenge the defeat via majority decision.

McGregor floored his opponent in round one and Diaz was downed twice more in the second round, but the Irishman survived a series of brutal blows in the third.

Diaz scored a takedown late in the fifth but McGregor saw out the time with the three judges scoring it 48-47, 47-47, 48-47, leading to a famous declaration: "The king is back!"

January 18, 2020 – McGregor beats Cerrone by knockout

Five months on from the ugly aftermath of the Khabib defeat, McGregor announced, "I've decided to retire from the sport formally known as 'Mixed Martial Art'."

High-profile incidents away from the Octagon had plagued McGregor, while he also launched his 'Proper No. Twelve' whiskey brand.

Still, the lure of the UFC proved too much for one of the all-time greats and a focused McGregor was back to fight Cerrone in Las Vegas in a bout pitting two of the sport's most popular stars against one another.

McGregor put on an absolute clinic and a series of brutal blows led to the bout being waved off after just 40 seconds. It marked his first victory in the Octagon since November 2016 when he defeated Eddie Alvarez to win the UFC lightweight title and become the company's first ever dual champion.

After the fight, McGregor said: "I made history tonight. I set a new record. I'm the first fighter in UFC history to secure knockout victories at featherweight, at lightweight and now at welterweight - across three weight divisions, so I'm very proud of that."

January 23, 2021 – McGregor v Poirier?

"Hey guys I've decided to retire from fighting. Thank you all for the amazing memories! What a ride it's been!"

And with that McGregor was done... again.

But really we knew he wasn't, and once more McGregor will step into the Octagon against an opponent he is familiar with.

Almost seven years have passed since McGregor earned 'Performance of the Night' honours after the fight was stopped after one minute and 46 seconds of the first round when 'The Notorious' put Poirier on the back foot then caught his opponent with a huge left hook behind the ear.

So the question remains: how will McGregor fare on his latest comeback from 'retirement'?