Unbeaten middleweight world champion Christina Hammer has sent out a message to her rival 160-pound champion Claressa Shields as she prepares to travel stateside for a press conference next Tuesday in New York City to officially announce their battle for the undisputed women’s middleweight championship Saturday, April 13 live on SHOWTIME from Boardwalk Hall in Atlantic City, N.J.

Hammer became the first German fighter to successfully defend their title in the U.S. since Max Schmeling, when she defeated Tori Nelson in June on SHOWTIME from Detroit. A win on April 13 would make her just the second undisputed champion in female boxing history.

“I’m looking forward to fighting Claressa in the U.S.,” said Hammer in the video. “This fight against Claressa is the biggest fight there is. It’s the biggest fight in the history of female boxing. It’s a game changer. I’m doing everything I can in this training camp to beat her. Claressa’s fight against Hanna Gabriel showed that she is beatable. I’m going to do the job better than Gabriel.”

The two will meet in one of the biggest female boxing fights in history for the undisputed 160-pound title.