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Director Sofia Coppola's rocker boyfriend revealed the two are expecting their second child.

Phoenix frontman Thomas Mars broke the news to Chicago's WXRT in a backstage interview. "I heard the story that if you play Bach, [babies in the womb] get smarter," Mars said.

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When asked if Mars would be playing his latest album "Wolfgang Amadeus Phoenix" for the baby, Mars responded jokingly, "We have to study it. Not sure it's a good idea."

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Coppola, 38, and Mars have a 3-year-old daughter together named Romy. According to People.com, Coppola, best known for her films "Lost in Translation" and "Marie Antoinette," is currently in post-production on her new movie "Somewhere," starring Michelle Monaghan and Benicio Del Toro.

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