The films will premiere this autumn on BBC Four as part of a special drama season.
"These films are sympathetic but frank dramatisations of women in the spotlight and how their backstage lives play out," said BBC Four controller Richard Klein.
"Once again, BBC Four is championing strong dramas that seek to give insight into some of Britain's most famous artists, reflecting complex lives, conflicting pressures and very human behaviour."
Jane Horrocks will portray singer-comedienne Fields in Nick Vivian's romantic comedy Gracie!, which will feature songs such as 'Sally' and 'Sing As We Go'.
Anne-Marie Duff is cast as Fonteyn in Amanda Coe's film about the famous dancer, while Blyton will be played by Helena Bonham Carter, who stars alongside Matthew Macfadyen and Denis Lawson in the drama.