British world champion Caroline Dubois has split with trainer Shane McGuigan and will be relocating to America.
The unified lightweight champion will defend her WBC and WBO titles against American Amelia Moore on 29 August on an all-female Most Valuable Promotions (MVP) card in Birmingham.
Dubois, 25, confirmed she and McGuigan had mutually agreed to part ways after working together since she turned professional in 2021.
She told BBC Sport: "I had a phenomenal time with Shane. There's been no bitterness, no break-up, no clash, no drift.
"This is the next step I need to help me progress."
Dubois did not reveal the identity of her new trainer, although it is understood she will now work with American coach Manny Robles.
The news emerged just hours before Wednesday's news conference in London, where the British and American fighters gathered to promote the UK v USA-themed event.
The event at BP Pulse Live arena will be headlined by a light-middleweight unification bout between Britain's Chantelle Cameron, 35, and American Mikaela Mayer.
Also on the card, three-weight world champion Terri Harper, 29, returns for the first time since her defeat by Dubois, taking on Texas fighter Miranda Reyes.
Glaziers Hall, overlooking the River Thames, was decorated with banners highlighting each fighter's achievements, showcasing the depth of talent assembled for what is arguably one of the strongest women's boxing cards of the year.
Dubois' exchange with Moore began in light-hearted fashion, with the American joking Britons have "amazing manners", but need to put more salt on their food.
Moore, 36, then gifted Dubois a Los Angeles Lakers cap to "congratulate Caroline on becoming American".
The Londoner smiled throughout the exchange, but the playful moment quickly gave way to the confidence that has become a trademark of her public persona in recent years.
Once known as a quieter figure outside the ring, Dubois has increasingly embraced the spotlight and become one of women's boxing's most outspoken champions.
"I always say I'm on a quest for greatness," she said. "I want to be the best fighter you've ever seen. I want to step into the ring and set the stage alight."
If Dubois gets past Moore, she has targeted further unification fights. The WBA title is currently held by American Stephanie Han, while Turkey's Elif Nur Turhan holds the IBF belt.
Dubois also reiterated a fight with American Alycia Baumgardner remains high on her wishlist, but claimed her 32-year-old rival has shown little interest in making the bout happen
