Mariah Carey will direct and star in a Christmas movie.

The 45-year-old singer has never before taken a directorial role in films but has enlisted the help of 'Rush Hour' director Brett Ratner - the man behind her hit music videos 'We Belong Together' and 'Obsessed' - who will be her producer on the project.

Taking to Instagram to share her excitement about the film, she wrote: ''Can't wait to share my directorial debut with my lambs, on the Hallmark channel! Here I am at the announcement party. Look out for my Christmas movie this December.''

The film is set for release in December on the Hallmark channel.

Rumours of the star's directorial debut circulated in April but confirmation the project was going ahead was only announced at a launch party for the 'Mariah Carey's Christmas Project' on Thursday night (30.07.15).

Filming for the straight-to-television project is due to start this autumn but no hints have been given about the storyline.

The pop singer's previous acting roles include a school teacher in 2009's 'Precious'.