Liam Smith has warned Josh Kelly he has made a mistake in agreeing to their fight on September 21.

The talented Kelly enters the biggest fight of his career on the undercard of the IBF heavyweight title fight at Wembley Stadium between the champion Daniel Dubois and Anthony Joshua.

They fight at middleweight, and do so with the 30-year-old Kelly in the form of his career having stopped Placido Ramirez in December, and with Smith’s future in doubt at 35, after being stopped by Chris Eubank Jr 12 months before his scheduled fight with Kelly.

Smith likened the occasion to that when in 2021 he stopped Anthony Fowler, five months after the defeat in Russia by Magomed Kurbanov that meant him being written off, and he said: “This is a great fight on a huge card.  It's a fight that not many people thought about but now it's announced, they can see it's an interesting fight.

"My focus is on Josh Kelly; I am massively confident of winning. Josh and Adam [Booth, Kelly’s trainer] probably feel like they are getting me at right time. Fighters have made that mistake before, and they are doing the same thing.

"Josh has got to step up at some point and this might be his right time, but people have thought they are getting me at the right before – Anthony Fowler did so after I fought in Russia. I feel refreshed now, we have long enough to go, this has lit the fire in my belly.  Big respect for Josh and Adam, but business is business.”

The fight represents Kelly’s first at middleweight, and he said: “I'm a big 154 fighter so 160 will suit me.  I have nothing but respect for Liam, he has had a great career, he put Liverpool on the map – him and his brothers – and there is no bad blood between us. It's just business. Stylistically it's one of the best match-ups on the card.”

Kelly has been appearing on Wasserman Promotions on the British terrestrial television platform of Channel 5, and Kalle Sauerland, of Wasserman, said: “The main event is absolutely gigantic, but Kelly versus Smith could steal the show. Yes, it is the right time to fight Liam, at the right weight.  People who are around the scene know of Josh Kelly's potential and this is his time to shine, in front of 90,000 people at an iconic venue.

“But it's not about this being the right time to fight Liam – it’s Josh's time. Adam Booth has done a fantastic job, this man is on fire.  I believe this fight will steal the show."