Klass starts at 7am on February 12 at the classical music station, which the singer and classical musician says she has listened to since its launch.
Before rising to fame when HearSay came together on reality ITV series 'Popstars', Klass studied classical instruments such as the piano and harp and graduated from the Royal Academy of Music.
After HearSay disintegrated, Klass recorded a classical music album, 'Moving On', in 2004, and has become a TV presenter with stints on ITV1's Saturday morning show 'CD:UK' and Channel 4's 'Popworld'.
Darren Henley, station manager at Classic FM, said: "Myleene's a sparkling new talent for Classic FM. As soon as I heard her behind the microphone, I knew she'd be a perfect fit for Sunday mornings."
Classic FM is owned by GCap and broadcasts across the UK. The latest Rajar radio audience figures for the third quarter of 2005 show its share of listening is down year-on-year from 4.2% to 4.1%.
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