Tyson Fury says he would "love" to take up Anthony Joshua's offer of sparring before he faces Deontay Wilder.
Fury, 31, drew with WBC world heavyweight champion Wilder in 2018 and is set for a rematch on 22 February.
Joshua, who holds the IBF, WBA and WBO belts, feels Fury would be more likely to agree to a fight for all four titles and offered to help his fellow Briton.
"I would love to have you in camp, work out for this fight and give Deontay Wilder a proper beating," said Fury.
"I hope you mean it, as I'd love to have you in training camp with me. When I do beat Wilder I will fight you AJ no problem."
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Fury offered his "congratulations" to Joshua for his win over Andy Ruiz Jr on 7 December, where he reclaimed his world titles after losing to the Mexican in June.
Joshua says he has already been "studying" Oleksandr Usyk, who he could face in the short term given the Ukrainian fighter's status as mandatory challenger with the WBO.
Bulgaria's Kubrat Pulev is also a mandatory challenger with the IBF, meaning the prospect of any fight between Joshua and Fury or Wilder still appears some time away.
Fury's bout with 34-year-old Wilder is said to be taking place in Las Vegas, although no venue has yet been confirmed for the bout.
"I think honestly he might beat Wilder next time," Joshua told Sky Sports News.
"I think Fury would fight me quicker than Wilder would, so if that's the case I want him to win. Imagine that fight on British soil.
"If Tyson needs me, I'll go out and spar with him to get him ready for Wilder."
Fury is currently in the process of joining up with new trainer Javan 'Sugar' Hill having parted company with Ben Davison.