Mariah Carey is working on a holiday film with rumoured producer boyfriend Brett Ratner.

The pop star and Rush Hour director sparked rumours of a romance earlier this year (15) when they were spotted vacationing together on the island of St. Barts.

Both denied the claims, insisting they have been friends for nearly two decades, as Ratner has directed a number of her music videos.

Now Carey insists the reasons they've been spending so much time together is purely professional, as they have a new holiday film in the works.

When asked by Buzzfeed what her favourite holiday film is, Carey replied, "My favorite holiday movie has yet to be filmed. Brett Ratner and I have a new movie and we're working with New Line Cinema and we're very excited.

"It was my idea, I brought it to them, I am executive-producing it. I am not the star of the movie, but my music is the star, and I have a very integral part in the movie. And it's exciting."