The service will sit alongside a web channel that can be watched live or downloaded as vodcasts.
It will offer a stream of playlists around genres including opera, chill and movie soundtracks, plus channels dedicated to popular Classic FM features, Smooth Classics and the Hall of Fame.
Listeners tuning in to the streams, which can be accessed via MyClassicFM.co.uk, will be invited to rate each track, so that future visits to the site will tailor tracks to individual tastes.
The sites will have an, as yet unconfirmed, solus advertiser when the online services launch on 7 January.
Traditional spot advertising will also be available in the future.
Darren Henley, managing director of Classic FM, said: "It's very important to us to create a community of interest around classical music."
Classic FM expects the move will allow it to expand its online database of 500,000 listeners.
The station's website recently launched The Arts Daily, plus a listen again service.