In My Dreams will be released in time for Mother's Day on March 12, and will feature cover versions of U2's 'With Or Without You', Bob Dylan's 'Make You Feel My Love' and Coldplay's 'Fix You' among others.
It will also feature their number one single 'Wherever You Are', which beat X Factor winners Little Mix to the Christmas top spot last year.
Group member Laura Thompson told Sky News: "It's just amazing, I'm so proud to be part of something that helps other people. I'm in awe."
Susie Brady added: "Obviously we didn't expect any of this so to have a single and an album and to raise so much for charities that are so personal for us - I'm over the moon."
Of the album project, Gareth Malone explained: "It means so much to me personally because this is the biggest thing I've ever done.
"I can't top this. I'm so proud of the association with these women. They're incredible for what they achieve on a daily basis but this has just distilled into something that the nation will never forget."
Soloist Sam Stephenson had previously spoken of her hopes of a possible album release.
Watch the video for 'Wherever You Are' below: