James Toney says Anthony Joshua has to put his "big-boy pants" on and head to America to face Deontay Wilder if he wants to prove he is the best.
The three-weight world champion is over in the United Kingdom for an exhibition fight in Bristol this weekend, but wants the unbeaten IBF and WBA world champion to head across the pond.
'Lights Out' believes a unification fight with WBC holder Wilder is a 50-50 clash and although he is a fan of Joshua, he has urged him to prove how good he is, on American soil.
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All you have to do is put your big-boy pants on and come to the United States and get your ass whooped or you will smash him. Either.
"Why doesn't he come over to the States? Is everybody scared?" he told Toe 2 Toe podcast.
"Come to the United States to see if you're a great fighter or not, because the US has got the best. The best has got to fight the best.
"Boxing is in the United States, not the UK, so if you want to be known for your real-boy skills, you have to come to the US.
"I've gone to Italy, Japan, I've been everywhere, all you have to do is put your big-boy pants on and come to the United States and get your ass whooped or you will smash him. Either."
Toney, who fell short of being crowned a world heavyweight champion back in 2008, is not surprised to see Joshua carrying two world titles.
The defensive genius boxed in Prizefighter at York Hall four years ago on the same bill that saw 'AJ' move to 3-0 with a second-round KO of Hrvoje Kisicek.
Toney has also sparred with Wilder and although he was not overly impressed with him, he refused to rule him out of beating Joshua in America.
"I met Joshua when he was 2-0 and back then I said to him 'you're going to be a world champion' and to this day, he is," he said.
"I've had a few rounds with Deontay Wilder, and he wasn't great, but to me, it's not a love-hate situation.
"Who wins? It could be Wilder or Joshua. It's a 50-50, whoever lands the first meaningful one, wins."
There is more from James Toney in this week's Toe 2 Toe podcast, available on Wednesday evening.