Lawrence Okolie will be working with new trainer Shane McGuigan as the British and Commonwealth champion targets more titles at cruiserweight.
The unbeaten Hackney fighter had been trained by Barry Robinson for his fourth-round knockout win over Wadi Camacho in March, but has now become the latest addition to McGuigan's gym.
Okolie announced the switch on social media, stating: "The work has already begun. Excited to be working with @shanemcguigan moving forward.
"I expect dangerous and clean performances."
McGuigan has been preparing Josh Taylor to challenge Ivan Baranchyk for the IBF super-lightweight title next Saturday, live on Sky Sports, and also works with top lightweight contender Luke Campbell.
He wrote on social media: "I'd like to welcome @lawrence_tko to McGuigan Gym. It's time to get serious."
Okolie had begun his career with trainer Brian O'Shaunnessy, racking up 10 wins before his brief spell with Robinson.