Spike O'Sullivan says he will feature on the undercard to Gennady Golovkin's rematch with Saul 'Canelo' Alvarez on September 15 at the T-Mobile Arena.

The Irish middleweight, who has lost just twice in his career, has been on a scintillating run of form in recent years and will now get the chance to perform for the first time in the fight capital of Las Vegas.

A row over the purse split had reportedly put the high-profile rematch in jeopardy, but O'Sullivan was confident a deal would eventually be reached for GGG-Canelo 2.

The 33-year-old, signed to American promotional company Golden Boy Boxing, has been promised a position on the undercard against a top-level opponent and 'Spike' believes victory will put him in line to face the winner of the much-anticipated main event.

I've been promised a spot on the GGG-Canelo undercard before being in line to face the winner. Spike O'Sullivan

"I've always said that I thought the rematch would get made, the money involved is too good to turn down," O'Sullivan said, speaking exclusively to Sky Sports.

"I have a five-fight contract with Golden Boy, with three still remaining, and they promised me, after my last fight, that I would be on this September undercard before being in line to face the winner.

Golovkin and Canelo fought to a draw last year

"I'm already working in the gym, but at the moment there's no talks of opponent but I expect a top undercard bout.

"It's all coming together nicely and I'm grateful for my fan base which continues to grow. I believe I'm at my best and coming into my prime. I've said many times before, 'you can't put an old head on young shoulders'.

"I train seven days a week now, all in the gym and I walk around at only a few pounds above my fight weight so I definitely think the best is yet to come for me in my career."

A post shared by Gary Spike O'Sullivan (@garyspikeosullivan) on May 4, 2018 at 8:07pm PDT

O'Sullivan has become a leading contender at 160lbs and was previously in talks to face Daniel Jacobs and Golovkin, but the Cork favourite opted for the "better deal" his promoters set out for him.

"The Golovkin fight was close, we were in talks and I wanted it, but it kept dragging on and they were talking to other fighters," 'Spike' continued.

"The offer Golden Boy gave me, which is going exactly to plan, was impossible to turn down. I have a young family and it was a no-brainer, the figures involved are brilliant for me.

Watch back to when O'Sullivan kissed Chris Eubank Jr at the weigh-in preceding their 2015 fight Watch back to when O'Sullivan kissed Chris Eubank Jr at the weigh-in preceding their 2015 fight

"Eddie Hearn offered me the Jacobs fight as well which I accepted and was grateful for, but again I've got to think of the business side to things and what's best for me and my family.

"All my focus now is on September and then getting the winner. Canelo would, financially, be the bigger fight eventually, but I've always wanted to face 'GGG'. That's my dream fight, and I believe I can beat him and take his '0'."