In his new memoir, tennis legend Björn Borg writes that he was diagnosed with prostate cancer in 2023, the Associated Press reports.

Borg writes about his illness in Heartbeats, which Diversion Books will publish later this month. The press calls the book “a remarkable look at the making of sporting legend and, for readers who know nothing about tennis, a rare glimpse into an extraordinary, compelling life.”

Borg burst onto the tennis scene in the 1970s as a teenager, winning the French Open at 18. He would go on to win five more, and scored five wins at Wimbledon. He shocked the athletic world by retiring in 1983 when he was 26. A comeback attempt in the early 1990s fizzled.

He is the author of two previous books, The Björn Borg Story and My Life and Game, co-written with Eugene L. Scott.

In Heartbeats, Borg writes that he underwent surgery in 2024, and his cancer is now in remission.

“Now I have a new opponent in cancer—one I can’t control,” he writes. “But I’m going to beat it. I’m not giving up. I fight like every day is a Wimbledon final. And those usually go pretty well, don’t they?”

Heartbeats is slated for publication on September 23.

Michael Schaub is a contributing writer.