Yesterday Oprah Winfrey shot an episode of her show in Fort Campbell, Ky., with an audience of more than 600 expectant mothers. Oprah called it "The World's Biggest Baby Shower," and asked country stars Martina McBride and Kenny Chesney to help entertain the crowd. "Some of those pregnant ladies screamed so loud I was actually worried they might go into labor early!" said Kenny, who sang "There Goes My Life." Martina wowed the crowd with her tender ballad "In My Daughter's Eyes" -- and she even managed to get in a few words with Oprah backstage. "I don't mean to be a geek or anything," said Martina to Oprah, "but I just have to tell you what an inspiration you've been for me." After the taping, both Kenny and Martina went back to their busy lives. Martina went back home to Nashville to do an interview with Redbook magazine -- and Kenny flew back to the islands, where he was relaxing with his road crew on a post-tour vacation. To see the "Oprah" episode with Martina and Kenny, tune in next Monday, Sep. 27, when it's tentatively scheduled to air.