Mikaela Mayer’s jump to lightweight remains on schedule, but against a different opponent.

Mayer, the former inaugural Ring junior lightweight world champion, has a new opponent for her lightweight debut as she now will battle Swedish contender Lucy Wildheart in a 10-rounder for the WBC interim world title (not recognized by The Ring) tomorrow at London’s Copper Box Arena after her original opponent, Christina Linardatou, was forced to withdraw after not meeting British Boxing Board of Control requirements.

Mayer-Wildheart will be the co-feature to the heavyweight main event between Joe Joyce and Zhilei “Big Bang” Zhang.

Promoted by Queensberry Promotions, Joyce-Zhang, Mayer-Wildheart and undercard bouts will stream live and exclusively in the U.S. on ESPN+ beginning at 3 p.m. ET/12 p.m. PT.

Wildheart (10-1, 4 KOs), a 30-year-old boxer-puncher, enters this late-notice assignment riding a five-bout winning streak since a 10-round decision defeat to French standout Estelle Mossely. In 2021, she knocked out former Mayer foe Edina Kiss in the third round. Wildheart went 2-0 in 2022, winning a pair of six-round decisions on British soil.

A press release by Top Rank was used in this article.