Anthony Joshua has reiterated that Deontay Wilder is his "main objective" so Dillian Whyte will have to wait for a rematch.
IBF, WBA and WBO heavyweight champion Joshua will defend his belts against Andy Ruiz Jr on June 1, live on Sky Sports Box Office, and wants to agree an undisputed title fight against WBC holder Wilder.
"I'm not looking at Dillian anymore, I'm looking at Wilder, because he's got the belt," Joshua told Sky Sports.
I'm not looking at Dillian anymore, I'm looking at Wilder, because he's got the belt.
"Ruiz Jr? Provided I get past him, Wilder, that's my main objective. Simple as that."
Whyte was in the running to become Joshua's next opponent and avenge the only loss of his career, sustained in late-2015 with the British title on the line.
After knocking out Derek Chisora last December, Whyte was considered as a challenger for Joshua's world titles but couldn't agree a deal. Whyte will instead fight the unbeaten Oscar Rivas on July 20, live on Sky Sports Box Office.
"Dillian Whyte had his opportunity to fight me April 13," Joshua said. "Dillian had a chance to fight for the titles, he felt it was a low-ball offer, he wants to build his value and compete against Rivas.
"It's a tough fight, it's a very tough fight, but providing Dillian comes through, it [accelerates] him onto the next stage of where he's trying to get to and that's becoming heavyweight champion of the world."
The stakes were raised for Joshua's upcoming title defence when Wilder knocked out Dominic Breazeale inside a round last weekend.
Wilder then said about fighting Joshua: "It's going to happen, it will happen. I believe in all my heart it will happen. I don't want this to be a Lennox [Lewis] and [Riddick] Bowe situation, I definitely don't.
"The heavyweight division is so lit right now, it's on fire right now. I think it is our obligation, our duty to give the fans what they want."
Promoter Eddie Hearn added: "The fight with AJ and Wilder is the biggest fight in the sport and all being well [with Joshua vs Ruiz Jr] it must happen next - no excuses, this is the fight that will change the sport globally.
"It's a legacy fight and AJ wants it so bad. Two big, fast, dangerous and fearless world heavyweight world champions that can turn the lights out with a blink of the eye - it's a must."
An undisputed title fight with every major belt at stake would mean Whyte's wait for his first ever world title shot would be delayed further.
Whyte is ranked No 1 with the WBC but was overlooked for Wilder's most recent defence in favour of Breazeale.
WBC president Mauricio Sulaiman suggested Whyte could face Tyson Fury, who held Wilder to a draw last year, in an eliminator before challenging the champion.
Whyte told Sky Sports about Fury: "He went from saying 'I'm not fighting Dillian, the WBC should give him his chance, he's done everything he needs to do'.
"The next he says: 'I'll fight him and knock him out in six rounds'.
"He's always contradicting whatever he says. He says: 'I'm the lineal heavyweight champ, I don't need no belt, no sanctioning body, I'll fight any man, anywhere'. Then now he's saying: 'give me the WBC diamond belt and I'll fight Dillian'. He makes no sense.
"He needs something about him on his [social media] feed every day, so he just says some random stuff to get a bit of traction."
Watch Anthony Joshua's US debut against Andy Ruiz Jr, Katie Taylor's undisputed world lightweight title fight, Callum Smith's first world title defence and the undercard at Madison Square Garden in New York on June 1, live on Sky Sports Box Office.