Anthony Joshua visited four US-based trainers to consider if they could work alongside his long-time coach Rob McCracken.
"He has to speak to the people I may want to work with and see if he can work with them," Joshua told IFLTV about McCracken, ahead of next year's rematch with Oleksandr Usyk who took his IBF, WBA and WBO heavyweight titles.
Who are the US trainers, which legends did they previously train, and are they a good fit for Joshua?
When Amir Khan was shockingly knocked out by Danny Garcia in 2012, he turned to Hunter as his new trainer.
The relationship lasted for seven fights although those included stoppage losses to Saul 'Canelo' Alvarez and Terence Crawford.
But Hunter is defined by his work with Andre Ward, who was widely regarded as the world's pound-for-pound No 1 boxer in his pomp.
Hunter was in Ward's corner from his amateur days throughout a stunning pro career which ended with an unbeaten 32-0 record and world titles in two divisions.
Currently, the top heavyweight in Hunter's gym is Tony Yoka - the Frenchman who succeeded Joshua as the Olympic super-heavyweight gold medallist in 2016. Yoka is unbeaten in 11 as a pro.
Perhaps most significantly for Joshua is that his close friend Joshua Buatsi has already made the move to Hunter's Bay Area, California-based, gym.
Buatsi has won his first two fights with his new trainer and said about Hunter: "Very calm is the best way to describe him. He is very strategic, he says just enough. He is very, very positive and optimistic."
Shields was Mike Tyson's trainer for his unsuccessful final world heavyweight title fight against Lennox Lewis in 2002.
It was a relationship that lasted only one fight - Tyson, at the very end of his career, would only win one more fight afterwards.
Shields also trained Evander Holyfield and David Tua, as well as the legendary duo Pernell Whitaker and Arturo Gatti.
The most prominent heavyweight currently at Shields' Texas-based gym is Efe Ajagba, the Nigerian knockout artist. Like Joshua, Ajagba is in the process of rebuilding from a defeat.
Two-weight world champion, and reigning WBC middleweight titleholder, Jermall Charlo also works with Shields.
Guillermo Rigondeaux and Erislandy Lara, both two-weight world champions from Cuba, are in the same gym.
Reynoso is defined by his success alongside Saul 'Canelo' Alvarez, currently the best fighter in the world.
The Mexicans have been by each other's sides since Canelo was a young boy, and Reynoso has played a leading role in turning him into a four-weight world champion from his gym in San Diego, California.
Reynoso's has forged his own reputation as one of the world's best trainers through his tutelage of Canelo. His father, Chepo Reynoso, was a boxing trainer in Mexico.
Joshua's promoter Eddie Hearn retains a close relationship with Canelo's team.
Intriguingly Andy Ruiz Jr, the first man to beat Joshua, is also in Reynoso's gym.
Frank Sanchez, the Cuban heavyweight, Oscar Valdez, the WBC super-featherweight champion, and Ryan Garcia, one of US boxing's brightest hopes, are all under the same roof.
He is best known for being in the corner of his brother, Mikey Garcia, who is a four-weight world champion.
Nicknamed 'Grandpa', Robert Garcia was a super-featherweight world champion himself and, in tandem with his father Eduardo, has trained 13 world champions from his gym in Oxnard, California.
Nonito Donaire, also a champion in four divisions, notably trained under Garcia. Abner Mares is currently the WBA featherweight titleholder. Jose Ramirez, who lost an undisputed title fight to Josh Taylor, is also with Garcia.
The exciting welterweight prospect Vergil Ortiz Jr is also in the same gym.
October 31 - Top Rank in New York
Jose Zepeda vs Josue Vargas
November 6 - Top Rank in Las Vegas
Mikaela Mayer vs Maiva Hamadouche - IBF and WBO super-featherweight titles
November 6 - BOXXER in Liverpool
November 20 - BOXXER in London
Richard Riakporhe vs Olanrewaju Durodola
Caroline Dubois professional debut
Hosea Burton vs Dan Azziz - British light-heavyweight title
November 20 - Top Rank in Las Vegas
Terence Crawford vs Shawn Porter - WBO welterweight title
December 11 - BOXXER
December 11 - Top Rank in Las Vegas
Vasiliy Lomachenko vs Richard Commey
December 17 - Top Rank in Montreal
Artur Beterbiev vs Marcus Browne - IBF and WBC light-heavyweight titles
February 26 - Top Rank in Glasgow
Josh Taylor vs Jack Catterall - undisputed super-lightweight title