“I just knew Whitney would kill it,” he says.

“Whitney actually sang that as a teenager in her mother’s church.

So she knew the song very well.”

The Preacher’s Wife

Credit: Everett Collection; Inset: Jeffrey Mayer/WireImage

Recording it was so much fun because Houston “never sang anything the same way twice.”

Warren recorded the Georgia Mass Choir singing his jubilant rendition of the Christmas classic in the space.

We [needed] to strike a balance," says Warren, explaining the dual recording scenarios.

“I said, ‘Listen, let’s just do it another day.’

And she said, ‘No, I have to do it.

It’s a simple song.

I’ll get through it,'” says Warren.

To read more on holiday film favorites,order the December issueofEntertainment Weeklyor find on newsstands now.