Andrea Jaeger!

Twenty-five years ago, Andrea Jaeger was the brat of the women’s tennis tour. While rising to No. 2 in the world, she tells PEOPLE she sometimes screamed at linesmen and was standoffish to competitors.

Cut to the present: The former tennis star, surrounded by a gaggle of young cancer survivors, strolls the halls of Cincinnati Children’s Hospital. At each room the gang stops and belts a splendidly off-key version of "Somewhere Over the Rainbow." In their beds, other kids giggle.

Jaeger’s worldview has changed dramatically: On. Sept. 16 the former tennis terror became, officially, Sister Andrea, an Anglican Dominican nun. Now 41, she has dedicated her life to the care of kids in need, visiting hospitals and running camps for kids with cancer.

Sister Andrea says that even when she was on the tour, there was a more spiritual soul lurking beneath. She says she always felt that "God had a plan" for her.

The last time I was at the Christian Booksellers’ Association convention, she was there, signing – the line was pretty long, though, so I didn’t get a book…

More from Beliefnet and our partners