Titled 'The Month', the CD-ROM is scheduled for launch at the end of August and will feature seven interactive channels devoted to subjects such as film, music, TV and entertainment features.
It will be a regular monthly section, increasing The Sunday Times package to a total of 14 sections.
It hopes to attract younger readers to The Sunday Times who have grown up in the age of the internet and have never acquired a regular newspaper-reading habit.
The secret project has not been communicated to media agencies. Rather, The Sunday Times has been talking directly to advertisers in entertainment categories. An overall sponsor is being sought, as are sponsors for each subject channel.
The Sunday Times sees 'The Month' as a way to reach younger people who view newspapers as an outdated medium. An advertising campaign will be announced shortly.
"It's a massive project for The Sunday Times - truly revolutionary - and a welcome kick up the backside for national newspapers," said one advertising source.