The Little Mix star is set to star in Aml Ameen's directional debut along with the likes of 'How to Get Away with Murder' star Aja Naomi King and 'Secrets & Lies' actress Marianne Jean-Baptiste.
The 29-year-old pop star took to her Instagram Stories to confirm the news by sharing a screenshot of Deadline's report of the announcement.
It's not currently known what character Leigh-Anne will portray.
The plot is as follows: "Melvin (Ameen), a British author living in America, returns home to London for Christmas to introduce his American fiancée Lisa (King) to his eccentric British-Caribbean family. Their relationship is put to the test, as she discovers the world her fiancé has left behind."
Aml said: “It is such an honour to be teaming up with Warner Bros. Pictures, Film4 and BFI to bring Black British Culture to the world in this universal holiday rom-com. It’s long been a dream of mine to capture films that reflect the wonderfully multi-cultural city that raised me while sharing stories from the diary of my life."
The 'Yardi' star's directional debut comes after he starred alongside Michaela Coel in the hit TV drama 'I May Destroy You'.
Meanwhile, 'Sweet Melody' hitmaker Leigh-Anne recently setup her own Pinnock Productions firm.
Last month, it was revealed the company was registered on Companies House for deals with "artistic creation" in the TV world.
An insider claimed: "Leigh-Anne has spent almost a decade in the public eye thanks to her success with Little Mix and has become really respected in the industry. She loves the idea of doing more work in TV and has set up this company with a view to being more involved. Pinnock Productions is all about making waves within the TV industry.
"They want to bring to the screen shows that have never been done before — fresh and innovative projects that embrace diversity and cultures that should have their place on screen.
"It could give her massive opportunities to get behind the camera and establish herself as a producer in her own right."