The Notorious Conor McGregor takes on Eddie Alvarez this weekend in a bout which could see him crowned the UFC's first ever two-weight World Champion.
The Dublin fighter has lost just one bout in his UFC career - a second-round stoppage to Nate Diaz - but took his revenge on the Californian at UFC 202 via majority decision.
And now McGregor is heading back into the octagon to try and add the lightweight belt to the featherweight belt he already holds.
Here we look through everything you need to know ahead of the UFC's most hotly-anticipated event yet.
When is it?
The main card gets under way at 3am on Sunday November 13, with five fights scheduled ahead of McGregor's headline bout.
UFC president Dana White believes the main card is the best the company has ever put on and it's hard to disagree with that - with three title fights to take place during UFC 205.
Even UFC stalwart Frankie Edgar and the unbeaten Khabib Nurmagomedov only make it onto the preliminary card.
The main card is as follows:
Women's bantamweight : Miesha Tate v Raquel Pennington
Welterweight : Kelvin Gastelum v Donald Cerrone
Middleweight : Chris Weidman v Yoel Romero
Women's strawweight : Joanna Jedrzejczyk (Champion) v Karolina Kowalkiewicz
Welterweight : Tyron Woodley (Champion) v Stephen Thompson
Lightweight : Eddie Alvarez (Champion) v Conor McGregor
Where is it?
UFC 205 will be the first event held by the Ultimate Fighting Championships in New York after several years of campaigning.
The state imposed a ban on the sport in 1997, but lifted the ruling in April this year.
And after a 19-year wait to take the sport to New York, the UFC has pulled out all the stops.
The fights will take place at Madison Square Garden in Manhattan - one of the most famous venues in the world.
What are they fighting for?
McGregor and Alvarez will be contesting the American's lightweight belt.
The Notorious took the featherweight belt in December last year after knocking out the then undefeated champion Jose Aldo Jr, before stepping up a weight division to take on Rafael dos Anjos for the lightweight belt.
Dos Anjos pulled out however and McGregor has had to wait for his chance to take the belt in the weight division above.
McGregor previously held the Cage Warriors belts in the same divisions - the first person to hold both at the same time - before vacating the belts for the UFC.
How can I watch it?
BT Sport 2 are broadcasting the main card as well as a preliminary card in the UK.
A UFC Fight Pass is needed to watch the preliminary bout.
The event is scheduled for 1am to 7am on BT Sport, but it's anybody's guess when the McGregor v Alvarez fight will start.
Tale of the tape
Leg reach (in)
What has been said?
"Wherever I choose to go, I’m prepared to go there.
"I feel great at this weight. Obviously, it’s tougher to get to featherweight, but I think it’s crazy the way they say I can’t get to featherweight no more or all these crazy things. Like I haven’t gone in there and taken out the whole division as early as last year.
"Then they’re talking about stripping [my title] and vacating and all this stuff, it’s like hold on a minute — what did I just go and do there? Am I not champion?
"I can defend them both [lightweight and featherweight titles]. Vacate? We’ll see about that. I fight every week."
"This guy is so offensive-minded and never on the defence, that whenever you put him on the defence he gets so flustered and so upset.
"At a certain point in our press conference call he got desperate. He started talking about my wife and kids and things like that. That for me is just a sign of desperation.
"If we were in a fight and I was putting him on the defence, I looked at this like this man is just closing his eyes throwing 'Bolos'. Just to see him cross that, it's good. It's a good sign for me."
What are the odds?
Conor McGregor is at 8/13 to win, with Eddie Alvarez at 5/4.
The Notorious is 1/1 to win by TKO/KO, 16/1 by submission and 15/2 by decision.
Alvarez is 9/2 to win by TKO/KO and submission and 11/2 to win by decision.
Who will win?
I'm going to go with McGregor to win.
The Irish fighter is a knockout specialist and it's hard to see Alvarez taking too many of his shots.
My bet would be the Notorious to win by TKO/KO in the second round at 13/2.
If Alvarez takes it I would go for by submission in the third at 33/1.