What was the song playing when Anne Hathaway introduced Josh Brolin & Javier Bardem during the 2011 Oscars?

Anne was just talking about the 1st Academy Awards held in 1929 at the Hollywood Roosevelt Hotel when it starts to play. The song was an instrumental (featuring a clarinet or a saxophone) and sounds like it's from the 30's. Josh & Javier then are seen dancing and the music stops as they begin their presentation for the award for Best Adapted Screenplay.